Can now parse lambda lists

build.bat

@@ -2,7 +2,7 @@
 @setlocal
 pushd %~dp0
 
-set exeName=lisp.exe
+set exeName=slime.exe
 set binDir=bin
 
 mkdir quickbuild 2>nul

debug.bat

@@ -1,4 +1,4 @@
 @echo off
 pushd %~dp0\vs
-start lisp.sln
+start slime.sln
 popd

run.bat

@@ -4,6 +4,6 @@ pushd %~dp0\bin
 call ..\build.bat
 if %errorlevel% == 0 (
    echo ---------- Running ----------
-   call timecmd lisp.exe
+   call timecmd slime.exe
 )
 popd

src/ast.c

@@ -36,14 +36,77 @@ typedef struct {
 } Pair;
 
 typedef struct {
-    Pair* regular_params;
-    Pair* keyword_params;
-} Lambda_List;
+    struct Ast_Node** data;
+    int length;
+    int next_index;
+} Ast_Node_Array_List;
+
 
 typedef struct {
-    Lambda_List* parameters;
-    Pair* form;
-    char* docstring;
+    char** identifiers;
+    int next_index;
+    int length;
+} Positional_Arguments;
+
+typedef struct {
+    char** identifiers;
+    // values[i] will be nullptr if no defalut value was declared for
+    // key identifiers[i]
+    Ast_Node_Array_List* values;
+    int next_index;
+    int length;
+} Keyword_Arguments;
+
+
+Ast_Node_Array_List* create_Ast_Node_Array_List(int initial_length);
+void append_to_Ast_Node_Array_List(Ast_Node_Array_List* list, struct Ast_Node* node);
+
+Positional_Arguments* create_positional_argument_list(int initial_capacity) {
+    Positional_Arguments* ret = new(Positional_Arguments);
+    ret->identifiers = (char**)malloc(initial_capacity * sizeof(char*));
+    ret->next_index = 0;
+    ret->length = initial_capacity;
+    return ret;
+}
+
+void append_to_positional_argument_list(Positional_Arguments* args, char* identifier) {
+    if (args->next_index == args->length) {
+        args->length *= 2;
+        args->identifiers = (char**)realloc(args->identifiers, args->length * sizeof(char*));
+    }
+    args->identifiers[args->next_index++] = identifier;
+}
+
+Keyword_Arguments* create_keyword_argument_list(int initial_capacity) {
+    Keyword_Arguments* ret = new(Keyword_Arguments);
+    ret->identifiers = (char**)malloc(initial_capacity * sizeof(char*));
+    ret->values = create_Ast_Node_Array_List(initial_capacity);
+    ret->next_index = 0;
+    ret->length = initial_capacity;
+    return ret;
+}
+
+void append_to_keyword_argument_list(Keyword_Arguments* args,
+                                     char* identifier,
+                                     struct Ast_Node* default_value)
+{
+    if (args->next_index == args->length) {
+        args->length *= 2;
+        args->identifiers = (char**)realloc(args->identifiers, args->length * sizeof(char*));
+    }
+
+    args->identifiers[args->next_index++] = identifier;
+    append_to_Ast_Node_Array_List(args->values, default_value);
+}
+
+
+typedef struct {
+    char*  docstring;
+    Positional_Arguments* positional_arguments;
+    Keyword_Arguments*    keyword_arguments;
+    // rest_argument will be nullptr if no rest argument is declared
+    char*                 rest_argument;
+    struct Ast_Node* body; // implicit prog
 } Function;
 
 typedef enum {
@@ -134,12 +197,6 @@ struct Ast_Node {
 // was forward declarated
 typedef struct Ast_Node Ast_Node;
 
-typedef struct {
-    Ast_Node** data;
-    int length;
-    int next_index;
-} Ast_Node_Array_List;
-
 typedef struct {
     Ast_Node_Array_List* positional_arguments;
     // TODO(Felix): Really use hashmap (keyword[sting] ->

src/error.c

@@ -1,6 +1,7 @@
 typedef enum {
     Error_Type_Ill_Formed_List,
     Error_Type_Ill_Formed_Arguments,
+    Error_Type_Ill_Formed_Lambda_List,
     Error_Type_Wrong_Number_Of_Arguments,
     Error_Type_Unknown_Keyword_Argument,
     Error_Type_Type_Missmatch,
@@ -40,6 +41,7 @@ char* Error_Type_to_string(Error_Type type) {
     switch (type) {
     case Error_Type_Ill_Formed_List:           return "Evaluation-error: Ill formed list";
     case Error_Type_Ill_Formed_Arguments:      return "Evaluation-error: Ill formed arguments";
+    case Error_Type_Ill_Formed_Lambda_List:    return "Evaluation-error: Ill formed lambda list";
     case Error_Type_Unknown_Keyword_Argument:  return "Evaluation-error: Unknown keyword argument";
     case Error_Type_Not_A_Function:            return "Evaluation-error: Not a function";
     case Error_Type_Symbol_Not_Defined:        return "Evaluation-error: Symbol not defined";

src/eval.c

@@ -1,7 +1,140 @@
-/* Ast_Node* apply_to_lambda () {} */
 
-Ast_Node* eval_expr(Ast_Node* node, Environment* env);
-bool is_truthy (Ast_Node* expression, Environment* env);
+Ast_Node* apply_arguments_to_function (Ast_Node* arguments, Ast_Node* function) {
+    printf("calling function, yey\n");
+
+    return create_ast_node_nil();
+}
+
+/**
+   This parses the argument specification of funcitons into their
+   Function struct. It dois this by allocating new
+   positional_arguments, keyword_arguments and rest_argument and
+   filling it in
+*/
+void parse_argument_list(Ast_Node* arguments, Function* function) {
+    // first init the fields
+    function->positional_arguments = create_positional_argument_list(16);
+    function->keyword_arguments    = create_keyword_argument_list(16);
+    function->rest_argument        = nullptr;
+
+    // okay let's try to read some positional arguments
+    while (arguments->type == Ast_Node_Type_Pair) {
+        if (arguments->value.pair->first->type == Ast_Node_Type_Keyword) {
+            if (string_equal(arguments->value.pair->first->value.keyword->identifier, "keys") ||
+                string_equal(arguments->value.pair->first->value.keyword->identifier, "rest"))
+                break;
+            else {
+                create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+                return;
+            }
+        }
+
+        if (arguments->value.pair->first->type != Ast_Node_Type_Symbol) {
+            create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+            return;
+        }
+
+        // okay wow we found an actual symbol
+        append_to_positional_argument_list(
+            function->positional_arguments,
+            arguments->value.pair->first->value.symbol->identifier);
+
+        arguments = arguments->value.pair->rest;
+    }
+
+    // okay we are done with positional arguments, lets check for
+    // keywords,
+    if (arguments->type != Ast_Node_Type_Pair) {
+        if (arguments->type != Ast_Node_Type_Nil)
+            create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+        return;
+    }
+
+    if (arguments->value.pair->first->type == Ast_Node_Type_Keyword &&
+        string_equal(arguments->value.pair->first->value.keyword->identifier, "keys"))
+    {
+        arguments = arguments->value.pair->rest;
+        if (arguments->type != Ast_Node_Type_Pair ||
+            arguments->value.pair->first->type != Ast_Node_Type_Symbol)
+        {
+            create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+            return;
+        }
+
+        while (arguments->type == Ast_Node_Type_Pair) {
+            if (arguments->value.pair->first->type == Ast_Node_Type_Keyword) {
+                if (string_equal(arguments->value.pair->first->value.keyword->identifier, "rest"))
+                    break;
+                else {
+                    create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+                    return;
+                }
+            }
+
+            if (arguments->value.pair->first->type != Ast_Node_Type_Symbol) {
+                create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+                return;
+            }
+
+            // we found a symbol (arguments->value.pair->first) for
+            // the keyword args! Let's check if the next arguement is
+            // :defaults-to
+            Ast_Node* next = arguments->value.pair->rest;
+            if (next->type == Ast_Node_Type_Pair &&
+                next->value.pair->first->type == Ast_Node_Type_Keyword &&
+                string_equal(next->value.pair->first->value.keyword->identifier,
+                              "defaults-to"))
+            {
+                // check if there is a next argument too, otherwise it
+                // would be an error
+                next = next->value.pair->rest;
+                if (next->type == Ast_Node_Type_Pair) {
+                    append_to_keyword_argument_list(function->keyword_arguments,
+                                                    arguments->value.pair->first->value.symbol->identifier,
+                                                    next->value.pair->first);
+                    arguments = next->value.pair->rest;
+                } else {
+                    create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+                    return;
+                }
+            } else {
+                // No :defaults-to, so just add it to the list
+                append_to_keyword_argument_list(function->keyword_arguments,
+                                                arguments->value.pair->first->value.symbol->identifier,
+                                                nullptr);
+                arguments = next;
+            }
+        }
+    }
+
+
+    // Now we are also done with keyword arguments, lets check for
+    // if there is a rest argument
+    if (arguments->type != Ast_Node_Type_Pair) {
+        if (arguments->type != Ast_Node_Type_Nil)
+            create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+        return;
+    }
+
+    if (arguments->value.pair->first->type == Ast_Node_Type_Keyword &&
+        string_equal(arguments->value.pair->first->value.keyword->identifier, "rest"))
+    {
+        arguments = arguments->value.pair->rest;
+        if (arguments->type != Ast_Node_Type_Pair ||
+            arguments->value.pair->first->type != Ast_Node_Type_Symbol)
+        {
+            create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+            return;
+        }
+        function->rest_argument = arguments->value.pair->first->value.symbol->identifier;
+        if (arguments->value.pair->rest->type != Ast_Node_Type_Nil) {
+            create_error(Error_Type_Ill_Formed_Lambda_List, arguments);
+        }
+    } else {
+        printf("this should not happen?");
+        create_error(Error_Type_Unknown_Error, arguments);
+    }
+}
 
 
 int list_length(Ast_Node* node) {
@@ -56,6 +189,9 @@ Ast_Node* copy_list(Ast_Node* node) {
     return result;
 }
 
+Ast_Node* eval_expr(Ast_Node* node, Environment* env);
+bool is_truthy (Ast_Node* expression, Environment* env);
+
 Parsed_Arguments* eval_and_parse_arguments(Ast_Node* arguments, Environment* env) {
     // TODO(Felix): if arguments is nil then maybe return a constant
     // Parsed_Arguments_nil?
@@ -70,9 +206,9 @@ Parsed_Arguments* eval_and_parse_arguments(Ast_Node* arguments, Environment* env
     Parse_State parse_state = Expecting_Anything;
 
     Parsed_Arguments* result = new(Parsed_Arguments);
-    result->positional_arguments = create_Ast_Node_Array_List();
-    result->keyword_keys         = create_Ast_Node_Array_List();
-    result->keyword_values       = create_Ast_Node_Array_List();
+    result->positional_arguments = create_Ast_Node_Array_List(16);
+    result->keyword_keys         = create_Ast_Node_Array_List(16);
+    result->keyword_values       = create_Ast_Node_Array_List(16);
 
     Ast_Node* current_head = copy_list(arguments);
     Ast_Node* current_evaluated_head;
@@ -171,6 +307,47 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
         // check for special form
         if (operator->type == Ast_Node_Type_Built_In_Function) {
             switch (operator->value.built_in_function->type) {
+            case Built_In_Lambda: {
+                /*
+                 *  (lambda ())
+                 *  (lambda (x d) (+ 1 2) (- 1 2) (* 1 2))
+                 */
+                try {
+                    arguments_length = list_length(arguments);
+                }
+                if (arguments_length == 0)
+                    report_error(Error_Type_Wrong_Number_Of_Arguments);
+
+
+                Function* function = new(Function);
+                // if parameters were specified
+                if (arguments->value.pair->first->type != Ast_Node_Type_Nil) {
+                    try {
+                        assert_type(arguments->value.pair->first, Ast_Node_Type_Pair);
+                    }
+                    try {
+                        parse_argument_list(arguments->value.pair->first, function);
+                    }
+                }
+
+                arguments = arguments->value.pair->rest;
+                // if there is a docstring, use it
+                if (arguments->value.pair->first->type == Ast_Node_Type_String) {
+                    function->docstring = arguments->value.pair->first->value.string->value;
+                    arguments = arguments->value.pair->rest;
+                }
+
+                // we are now in the function body, just wrap it in an
+                // implicit prog
+                function->body = create_ast_node_pair(
+                    create_ast_node_built_in_function("prog"),
+                    arguments);
+
+                Ast_Node* ret = new(Ast_Node);
+                ret->type = Ast_Node_Type_Function;
+                ret->value.function = function;
+                return ret;
+            }
             case Built_In_And: {
                 bool result = true;
                 while (arguments->type != Ast_Node_Type_Nil) {
@@ -454,6 +631,13 @@ Ast_Node* eval_expr(Ast_Node* node, Environment* env) {
 
         // assume it's lambda function and evaluate the arguments
         arguments = eval_arguments(arguments, env, &arguments_length);
+        if (operator->type == Ast_Node_Type_Function) {
+            Ast_Node* result;
+            try {
+                result = apply_arguments_to_function(arguments, operator);
+            }
+            return result;
+        }
     }
 
     default:

src/init.c

@@ -14,5 +14,5 @@ void init () {
 #endif
 
     // TODO(Felix): Init the constants here (Bulit-in function
-    // ast_nodes, nil, ..more?)
+    // ast_nodes, nil, type_keywords ..more?)
 }

src/io.c

@@ -69,6 +69,7 @@ void print(Ast_Node* node) {
     } break;
     case (Ast_Node_Type_Function): {
         printf("[lambda]");
+        /* print(node->value.function->body); */
     } break;
     case (Ast_Node_Type_Built_In_Function): {
         printf("[built-in-function %s]", Built_In_Name_to_string(node->value.built_in_function->type));

src/parse.c

@@ -1,22 +1,23 @@
-Ast_Node_Array_List* create_Ast_Node_Array_List() {
+Ast_Node_Array_List* create_Ast_Node_Array_List(int initial_length) {
     Ast_Node_Array_List* ret = new (Ast_Node_Array_List);
 
     // create one with 16 entries first
-    ret->length = 16;
-    ret->data = (Ast_Node**)malloc(ret->length * sizeof(Ast_Node));
+    ret->length =  initial_length;
+    ret->data = (struct Ast_Node**)malloc(initial_length * sizeof(struct Ast_Node));
     ret->next_index = 0;
 
     return ret;
 }
 
-void append_to_Ast_Node_Array_List(Ast_Node_Array_List* list, Ast_Node* node) {
+void append_to_Ast_Node_Array_List(Ast_Node_Array_List* list, struct Ast_Node* node) {
     if (list->next_index == list->length) {
         list->length *= 2;
-        list->data = (Ast_Node**)realloc(list->data, list->length * sizeof(Ast_Node));
+        list->data = (struct Ast_Node**)realloc(list->data, list->length * sizeof(struct Ast_Node));
     }
     list->data[list->next_index++] = node;
 }
 
+
 void eat_comment_line(char* text, int* index_in_text) {
     // safety check if we are actually starting a comment here
     if (text[*index_in_text] != ';')
@@ -237,7 +238,7 @@ Ast_Node* parse_single_expression(char* text) {
 }
 
 Ast_Node_Array_List* parse_program(char* text) {
-    Ast_Node_Array_List* program = create_Ast_Node_Array_List();
+    Ast_Node_Array_List* program = create_Ast_Node_Array_List(16);
 
     int index_in_text = 0;
 

test.bat

@@ -4,7 +4,7 @@ pushd %~dp0\bin
 call ..\build.bat
 if %errorlevel% == 0 (
    echo ---------- Testing ----------
-   call timecmd lisp.exe test.lsp
+   call timecmd slime.exe test.slime
 )
 
 popd

todo.html

@@ -0,0 +1,539 @@
+<!doctype html>
+<html lang="en">
+<head>
+<title></title>
+<!-- 2018-10-14 So 16:55 -->
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<meta name="generator" content="Org-mode">
+<meta name="author" content="Felix Brendel">
+
+<link  href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet">
+<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
+<style type="text/css">
+/* org mode styles on top of twbs */
+
+html {
+    position: relative;
+    min-height: 100%;
+}
+
+body {
+    font-size: 18px;
+    margin-bottom: 105px;
+}
+
+footer {
+    position: absolute;
+    bottom: 0;
+    width: 100%;
+    height: 101px;
+    background-color: #f5f5f5;
+}
+
+footer > div {
+    padding: 10px;
+}
+
+footer p {
+    margin: 0 0 5px;
+    text-align: center;
+    font-size: 16px;
+}
+
+#table-of-contents {
+    margin-top: 20px;
+    margin-bottom: 20px;
+}
+
+blockquote p {
+    font-size: 18px;
+}
+
+pre {
+    font-size: 16px;
+}
+
+.footpara {
+    display: inline-block;
+}
+
+figcaption {
+  font-size: 16px;
+  color: #666;
+  font-style: italic;
+  padding-bottom: 15px;
+}
+
+/* from twbs docs */
+
+.bs-docs-sidebar.affix {
+    position: static;
+}
+@media (min-width: 768px) {
+    .bs-docs-sidebar {
+        padding-left: 20px;
+    }
+}
+
+/* All levels of nav */
+.bs-docs-sidebar .nav > li > a {
+    display: block;
+    padding: 4px 20px;
+    font-size: 14px;
+    font-weight: 500;
+    color: #999;
+}
+.bs-docs-sidebar .nav > li > a:hover,
+.bs-docs-sidebar .nav > li > a:focus {
+    padding-left: 19px;
+    color: #A1283B;
+    text-decoration: none;
+    background-color: transparent;
+    border-left: 1px solid #A1283B;
+}
+.bs-docs-sidebar .nav > .active > a,
+.bs-docs-sidebar .nav > .active:hover > a,
+.bs-docs-sidebar .nav > .active:focus > a {
+    padding-left: 18px;
+    font-weight: bold;
+    color: #A1283B;
+    background-color: transparent;
+    border-left: 2px solid #A1283B;
+}
+
+/* Nav: second level (shown on .active) */
+.bs-docs-sidebar .nav .nav {
+    display: none; /* Hide by default, but at >768px, show it */
+    padding-bottom: 10px;
+}
+.bs-docs-sidebar .nav .nav > li > a {
+    padding-top: 1px;
+    padding-bottom: 1px;
+    padding-left: 30px;
+    font-size: 12px;
+    font-weight: normal;
+}
+.bs-docs-sidebar .nav .nav > li > a:hover,
+.bs-docs-sidebar .nav .nav > li > a:focus {
+    padding-left: 29px;
+}
+.bs-docs-sidebar .nav .nav > .active > a,
+.bs-docs-sidebar .nav .nav > .active:hover > a,
+.bs-docs-sidebar .nav .nav > .active:focus > a {
+    padding-left: 28px;
+    font-weight: 500;
+}
+
+/* Nav: third level (shown on .active) */
+.bs-docs-sidebar .nav .nav .nav {
+    padding-bottom: 10px;
+}
+.bs-docs-sidebar .nav .nav .nav > li > a {
+    padding-top: 1px;
+    padding-bottom: 1px;
+    padding-left: 40px;
+    font-size: 12px;
+    font-weight: normal;
+}
+.bs-docs-sidebar .nav .nav .nav > li > a:hover,
+.bs-docs-sidebar .nav .nav .nav > li > a:focus {
+    padding-left: 39px;
+}
+.bs-docs-sidebar .nav .nav .nav > .active > a,
+.bs-docs-sidebar .nav .nav .nav > .active:hover > a,
+.bs-docs-sidebar .nav .nav .nav > .active:focus > a {
+    padding-left: 38px;
+    font-weight: 500;
+}
+
+/* Show and affix the side nav when space allows it */
+@media (min-width: 992px) {
+    .bs-docs-sidebar .nav > .active > ul {
+        display: block;
+    }
+    /* Widen the fixed sidebar */
+    .bs-docs-sidebar.affix,
+    .bs-docs-sidebar.affix-bottom {
+        width: 213px;
+    }
+    .bs-docs-sidebar.affix {
+        position: fixed; /* Undo the static from mobile first approach */
+        top: 20px;
+    }
+    .bs-docs-sidebar.affix-bottom {
+        position: absolute; /* Undo the static from mobile first approach */
+    }
+    .bs-docs-sidebar.affix .bs-docs-sidenav,.bs-docs-sidebar.affix-bottom .bs-docs-sidenav {
+        margin-top: 0;
+        margin-bottom: 0
+    }
+}
+@media (min-width: 1200px) {
+    /* Widen the fixed sidebar again */
+    .bs-docs-sidebar.affix-bottom,
+    .bs-docs-sidebar.affix {
+        width: 263px;
+    }
+}
+</style>
+<script type="text/javascript">
+$(function() {
+    'use strict';
+
+    $('.bs-docs-sidebar li').first().addClass('active');
+
+    $(document.body).scrollspy({target: '.bs-docs-sidebar'});
+
+    $('.bs-docs-sidebar').affix();
+});
+</script>
+</head>
+<body>
+<div id="content" class="container">
+<div class="row"><div class="col-md-9"><h1 class="title"></h1>
+<div id="outline-container-sec-1" class="outline-2">
+<h2 id="sec-1"><span class="section-number-2">1</span> Arguments</h2>
+<div class="outline-text-2" id="text-1">
+<p>
+In Emacs lisp, keyword arguments must be passed in the same order as they were
+defined in, so <code>((lambda (a &amp;key b c) (+ a b c)) 1 3 :b 2)</code> will preduce an
+error, because <code>b</code> was passed as last argument but was defined as second argument.
+</p>
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2<span style="color: #839496;">)</span>         <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">3</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 <span style="color: #6c71c4;">:b</span> 2<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">3</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:b</span> 2 1<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error</span>
+</pre>
+</div>
+
+
+<p>
+But if mulitiple keyword arguments are defined, their ordering does not matter.
+</p>
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b <span style="color: #268bd2;">&amp;key</span> c <span style="color: #268bd2;">&amp;key</span> d<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 <span style="color: #6c71c4;">:d</span> 4 <span style="color: #6c71c4;">:c</span> 3 <span style="color: #6c71c4;">:b</span> 2<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">10</span>
+</pre>
+</div>
+
+<p>
+It is even possible to have a non keyword argument bewtween keyword arguments
+and when calling, switch the order.
+</p>
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b c <span style="color: #268bd2;">&amp;key</span> d<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 <span style="color: #6c71c4;">:d</span> 4  3 <span style="color: #6c71c4;">:b</span> 2<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">10</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b c <span style="color: #268bd2;">&amp;key</span> d<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 <span style="color: #6c71c4;">:d</span> 4  <span style="color: #6c71c4;">:b</span> 2 3<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error</span>
+</pre>
+</div>
+
+<p>
+However somehow it is not possible to flip the ordering at the first argument
+</p>
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 2 <span style="color: #6c71c4;">:b</span> 1<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">3</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a <span style="color: #268bd2;">&amp;key</span> b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:b</span> 2 1<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span><span style="color: #268bd2;">&amp;key</span> a b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:a</span> 2 1<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">3</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span><span style="color: #268bd2;">&amp;key</span> a b<span style="color: #b58900;">)</span> <span style="color: #b58900;">(</span>+ a b<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 <span style="color: #6c71c4;">:a</span> 2<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error</span>
+</pre>
+</div>
+
+<p>
+So it seems, positional arguments have to be at the exact position they were
+defined in, but keyword arguments can appear in any order, but at the places
+where keyword arguments have been defined.
+</p>
+</div>
+
+<div id="outline-container-sec-1-1" class="outline-3">
+<h3 id="sec-1-1"><span class="section-number-3">1.1</span> Idea</h3>
+<div class="outline-text-3" id="text-1-1">
+<p>
+Every argument can be set using keys, but keyword arguments always come strictly
+after positional arguments
+</p>
+
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2 3 4<span style="color: #839496;">)</span>             <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">ok</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2 <span style="color: #6c71c4;">:c</span> 2 <span style="color: #6c71c4;">:d</span> 1<span style="color: #839496;">)</span>       <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">ok</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2 <span style="color: #6c71c4;">:d</span> 1 <span style="color: #6c71c4;">:c</span> 2<span style="color: #839496;">)</span>       <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">ok</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:d</span> 1 1 2 <span style="color: #6c71c4;">:c</span> 2<span style="color: #839496;">)</span>       <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error, keyword arguments must come last</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2 <span style="color: #6c71c4;">:c</span> 2 <span style="color: #6c71c4;">:d</span> 1 <span style="color: #6c71c4;">:a</span> 2<span style="color: #839496;">)</span>  <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error, 'a' was passed two times</span>
+
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2 <span style="color: #6c71c4;">:d</span> 1<span style="color: #839496;">)</span>             <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error, c was not passed, but does not have a default value</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b c <span style="color: #6c71c4;">:default</span> 10 d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> 1 2 <span style="color: #6c71c4;">:d</span> 1<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">okay again</span>
+</pre>
+</div>
+
+<p>
+The drawback then is that you can never pass a keyword as a positional argument,
+because it will always try to assign the next argument to the variable defined
+by the keyword. You could still pass it as a keyword argument though. This is
+especially annoying because we want to use keywords as type identifiers.
+</p>
+
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span>= <span style="color: #2aa198;">(</span>type <span style="color: #2aa198;">"hello"</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:string</span><span style="color: #839496;">)</span>
+</pre>
+</div>
+
+
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp"><span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>i-wanna-get-a-kw<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:hey</span><span style="color: #839496;">)</span>                   <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error, unmatched value for keyword argument</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>i-wanna-get-a-kw<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:i-wanna-get-a-kw</span> <span style="color: #6c71c4;">:hey</span><span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">this would work again</span>
+</pre>
+</div>
+
+<p>
+Other Idea is to mark the place in the parameter list where keyword argumetns
+start and arguments before that are positional and will not be stuffed into
+key-value pairs and arguments after that will be keyword arguments
+</p>
+
+<div class="org-src-container">
+
+<pre class="src src-ebnf">&lt;lambda list&gt; -&gt; &lt;positional argument&gt;*
+                 [:keys ( &lt;keyword arguments&gt; [:defaults-to &lt;value&gt;])*]
+                 [(:rest &lt;rest argument&gt;)|(:body &lt;body argument&gt;)]
+</pre>
+</div>
+
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp">  <span style="color: #839496;">(</span>= <span style="color: #2aa198;">(</span>type <span style="color: #2aa198;">"hello"</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:string</span><span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">this will work again because (=) does</span>
+                             <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">not use keyword arguments</span>
+  <span style="color: #839496;">(</span><span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>i-wanna-get-a-kw<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span> <span style="color: #6c71c4;">:hey</span><span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">would work because of the same reason</span>
+
+  <span style="color: #839496;">(</span>define fun
+    <span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span><span style="color: #6c71c4;">:keys</span> a b c d<span style="color: #b58900;">)</span>
+      <span style="color: #b58900;">(</span>+ a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span><span style="color: #839496;">)</span>
+
+  <span style="color: #839496;">(</span>fun 1 2 3 4<span style="color: #839496;">)</span>             <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">okay</span>
+  <span style="color: #839496;">(</span>fun 1 2 <span style="color: #6c71c4;">:d</span> 3 <span style="color: #6c71c4;">:c</span> 4<span style="color: #839496;">)</span>       <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">okay</span>
+  <span style="color: #839496;">(</span>fun 1 2 <span style="color: #6c71c4;">:d</span> 3 <span style="color: #6c71c4;">:c</span> 4 <span style="color: #6c71c4;">:a</span> 2<span style="color: #839496;">)</span>  <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error, 'a' was passed two times</span>
+  <span style="color: #839496;">(</span>fun <span style="color: #6c71c4;">:c</span> 1 <span style="color: #6c71c4;">:b</span> 2 <span style="color: #6c71c4;">:d</span> 3 <span style="color: #6c71c4;">:a</span> 4<span style="color: #839496;">)</span> <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">okay</span>
+  <span style="color: #839496;">(</span>fun <span style="color: #6c71c4;">:c</span> 1 <span style="color: #6c71c4;">:b</span> 2 <span style="color: #6c71c4;">:d</span> 3 4<span style="color: #839496;">)</span>    <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">error, positional argument after keyword</span>
+                            <span style="color: #49974A; font-style: italic;">;; </span><span style="color: #49974A; font-style: italic;">and fun does not accept rest parameter</span>
+
+  <span style="color: #839496;">(</span>define fun2
+    <span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span><span style="color: #6c71c4;">:quoted</span> op a b <span style="color: #6c71c4;">:keys</span> c d <span style="color: #6c71c4;">:rest</span> r<span style="color: #b58900;">)</span>
+      <span style="color: #b58900;">(</span>print r<span style="color: #b58900;">)</span>
+      <span style="color: #b58900;">(</span>op a b c d<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span><span style="color: #839496;">)</span>
+
+&gt;&gt; <span style="color: #839496;">(</span>fun2 * 1 2 <span style="color: #6c71c4;">:c</span> 3 <span style="color: #6c71c4;">:d</span> 4 <span style="color: #2aa198;">"this"</span> <span style="color: #2aa198;">"can"</span> <span style="color: #6c71c4;">:be</span> <span style="color: #2aa198;">"whatever"</span><span style="color: #839496;">)</span>
+<span style="color: #839496;">(</span><span style="color: #2aa198;">"this"</span> <span style="color: #2aa198;">"can"</span> <span style="color: #6c71c4;">:be</span> <span style="color: #2aa198;">"whatever"</span><span style="color: #839496;">)</span>
+24
+
+
+&gt;&gt; <span style="color: #839496;">(</span>define print-before-eval <span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span><span style="color: #6c71c4;">:body</span> expr<span style="color: #b58900;">)</span>
+     <span style="color: #b58900;">(</span>print expr<span style="color: #b58900;">)</span>
+     <span style="color: #b58900;">(</span>eval expr<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span><span style="color: #839496;">)</span>
+&gt;&gt; <span style="color: #839496;">(</span>define r <span style="color: #2aa198;">(</span>print-before-eval <span style="color: #b58900;">(</span>+ 1 2 3<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span><span style="color: #839496;">)</span>
+<span style="color: #839496;">(</span>+ 1 2 3<span style="color: #839496;">)</span>
+&gt;&gt; r
+6
+
+</pre>
+</div>
+
+<p>
+Wait this does not work either because you won't be able to pass keywords into
+rest.
+</p>
+
+<p>
+<b>Unrealated Idea: Distinguish between functions and macros</b>
+</p>
+
+<p>
+The difference is really simple:
+</p>
+<dl class="org-dl">
+<dt> Function </dt><dd>like a lambda, but no argument is automatically quoted
+</dd>
+<dt> Macro </dt><dd>like a lambda, but every argument is automatically quoted
+</dd>
+</dl>
+
+<p>
+This is important, because a macro should not introduce a new environment, but
+use the one it lives in.
+</p>
+
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp">&gt;&gt; <span style="color: #839496;">(</span>define print-before-eval <span style="color: #2aa198;">(</span>macro <span style="color: #b58900;">(</span><span style="color: #6c71c4;">:rest</span> expr<span style="color: #b58900;">)</span>
+     <span style="color: #b58900;">(</span>print expr<span style="color: #b58900;">)</span>
+     <span style="color: #b58900;">(</span>eval expr<span style="color: #b58900;">)</span><span style="color: #2aa198;">)</span>
+
+</pre>
+</div>
+</div>
+</div>
+
+<div id="outline-container-sec-1-2" class="outline-3">
+<h3 id="sec-1-2"><span class="section-number-3">1.2</span> the actual problem</h3>
+<div class="outline-text-3" id="text-1-2">
+<p>
+We have some requirements to the arguments:
+</p>
+<ul class="org-ul">
+<li>positional arguments (always required, no default value)
+</li>
+<li>keyword arguments (always come after positionals), can be not passed if there
+is a default value
+</li>
+<li>We want to be able to have a rest paramter, where everything is dumped in to
+that exceeds the other parameters
+</li>
+</ul>
+
+<p>
+<b>The problem is, we have no way of knowing if the current keyword we are
+ reading is still part of the keyword block or part of the rest paramter.</b>
+</p>
+
+<p>
+Consider:
+</p>
+
+<div class="org-src-container">
+
+<pre class="src src-emacs-lisp">&gt;&gt; <span style="color: #839496;">(</span>define fun <span style="color: #2aa198;">(</span><span style="color: #859900;">lambda</span> <span style="color: #b58900;">(</span>a b <span style="color: #6c71c4;">:key</span> c d <span style="color: #6c71c4;">:defaults-to</span> 4 <span style="color: #6c71c4;">:rest</span><span style="color: #b58900;">)</span> nil<span style="color: #2aa198;">)</span><span style="color: #839496;">)</span>
+&gt;&gt; <span style="color: #839496;">(</span>fun 1 2 <span style="color: #6c71c4;">:c</span> 3 <span style="color: #6c71c4;">:d</span> 5<span style="color: #839496;">)</span>
+</pre>
+</div>
+<p>
+What should this be evaluated to?
+</p>
+
+<table class="table table-striped table-bordered table-hover table-condensed">
+
+
+<colgroup>
+<col  class="left">
+
+<col  class="right">
+
+<col  class="right">
+
+<col  class="right">
+
+<col  class="right">
+
+<col  class="left">
+</colgroup>
+<thead>
+<tr>
+<th scope="col" class="text-left">&#xa0;</th>
+<th scope="col" class="text-right">a</th>
+<th scope="col" class="text-right">b</th>
+<th scope="col" class="text-right">c</th>
+<th scope="col" class="text-right">d</th>
+<th scope="col" class="text-left">rest</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td class="text-left">v1</td>
+<td class="text-right">1</td>
+<td class="text-right">2</td>
+<td class="text-right">3</td>
+<td class="text-right">5</td>
+<td class="text-left">nil</td>
+</tr>
+
+<tr>
+<td class="text-left">v2</td>
+<td class="text-right">1</td>
+<td class="text-right">2</td>
+<td class="text-right">3</td>
+<td class="text-right">4</td>
+<td class="text-left">(:d 5)</td>
+</tr>
+</tbody>
+</table>
+
+<p>
+It is ambiguous. It is however important to note that this can only happen when
+there are optinal keyword arguments (keyword arguments with default values).
+Otherwise we could always know which variables are set and wich have not been
+set to see if we are in an errornious state.
+</p>
+</div>
+</div>
+
+<div id="outline-container-sec-1-3" class="outline-3">
+<h3 id="sec-1-3"><span class="section-number-3">1.3</span> Solution</h3>
+<div class="outline-text-3" id="text-1-3">
+<p>
+We can resolve that problem by always making the the decision of chosing <code>v1</code>
+between <code>v1</code> and <code>v1</code>. This means, when we are expecting to read kwargs, and we
+encounter an kwarg, try to apply it (this can fail, for two reasons:
+</p>
+
+<ol class="org-ol">
+<li>The keyword has no following value
+</li>
+<li>The keyword is not a keyword argument in the funciton
+</li>
+</ol>
+
+<p>
+), if it fails treat it as part of the rest arguments, and read all the
+following arguments into the rest arguments, or if it works, use it as the
+keyword argument.
+</p>
+</div>
+</div>
+
+<div id="outline-container-sec-1-4" class="outline-3">
+<h3 id="sec-1-4"><span class="section-number-3">1.4</span> Implementation</h3>
+<div class="outline-text-3" id="text-1-4">
+<div class="org-src-container">
+
+<pre class="src src-c"><span style="color: #859900;">typedef</span> <span style="color: #859900;">struct</span> <span style="color: #839496;">{</span>
+    <span style="color: #268bd2;">char</span>*  <span style="color: #6c71c4;">docstring</span>;
+    <span style="color: #268bd2;">char</span>** <span style="color: #6c71c4;">positional_arguments</span>;
+    <span style="color: #859900;">struct</span> <span style="color: #2aa198;">{</span>
+        <span style="color: #268bd2;">char</span>* <span style="color: #6c71c4;">identifier</span>;
+        <span style="color: #268bd2;">Ast_node</span>* <span style="color: #6c71c4;">default_value</span>;    <span style="color: #49974A; font-style: italic;">// </span><span style="color: #49974A; font-style: italic;">will be nullptr if no defalut value was declared</span>
+    <span style="color: #2aa198;">}</span>* <span style="color: #6c71c4;">keyword_arguments</span>;
+    <span style="color: #268bd2;">char</span>*  <span style="color: #6c71c4;">rest_argument</span>;           <span style="color: #49974A; font-style: italic;">// </span><span style="color: #49974A; font-style: italic;">will be nullptr if no rest argument is declared</span>
+    <span style="color: #268bd2;">Ast_Node_array_list</span> <span style="color: #6c71c4;">body</span>;
+<span style="color: #839496;">}</span> <span style="color: #268bd2;">lambda</span>;
+</pre>
+</div>
+</div>
+</div>
+</div>
+</div><div class="col-md-3"><nav id="table-of-contents">
+<div id="text-table-of-contents" class="bs-docs-sidebar">
+<ul class="nav">
+<li><a href="#sec-1">1. Arguments</a>
+<ul class="nav">
+<li><a href="#sec-1-1">1.1. Idea</a></li>
+<li><a href="#sec-1-2">1.2. the actual problem</a></li>
+<li><a href="#sec-1-3">1.3. Solution</a></li>
+<li><a href="#sec-1-4">1.4. Implementation</a></li>
+</ul>
+</li>
+</ul>
+</div>
+</nav>
+</div></div></div>
+<footer id="postamble" class="">
+<div><p class="author">Author: Felix Brendel</p>
+<p class="date">Created: 2018-10-14 So 16:55</p>
+<p class="creator"><a href="http://www.gnu.org/software/emacs/">Emacs</a> 26.0.91 (<a href="http://orgmode.org">Org-mode</a> 9.1.13)</p>
+</div>
+</footer>
+</body>
+</html>

todo.org

@@ -1,3 +1,196 @@
+* Arguments
+
+In Emacs lisp, keyword arguments must be passed in the same order as they were
+defined in, so =((lambda (a &key b c) (+ a b c)) 1 3 :b 2)= will preduce an
+error, because =b= was passed as last argument but was defined as second argument.
+#+begin_src emacs-lisp
+  ((lambda (a b) (+ a b)) 1 2)         ;; 3
+  ((lambda (a &key b) (+ a b)) 1 :b 2) ;; 3
+  ((lambda (a &key b) (+ a b)) :b 2 1) ;; error
+#+end_src
+
+
+But if mulitiple keyword arguments are defined, their ordering does not matter.
+#+begin_src emacs-lisp
+  ((lambda (a &key b &key c &key d) (+ a b c d)) 1 :d 4 :c 3 :b 2) ;; 10
+#+end_src
+
+It is even possible to have a non keyword argument bewtween keyword arguments
+and when calling, switch the order.
+#+begin_src emacs-lisp
+  ((lambda (a &key b c &key d) (+ a b c d)) 1 :d 4  3 :b 2) ;; 10
+  ((lambda (a &key b c &key d) (+ a b c d)) 1 :d 4  :b 2 3) ;; error
+#+end_src
+
+However somehow it is not possible to flip the ordering at the first argument
+#+begin_src emacs-lisp
+  ((lambda (a &key b) (+ a b)) 2 :b 1) ;; 3
+  ((lambda (a &key b) (+ a b)) :b 2 1) ;; error
+  ((lambda (&key a b) (+ a b)) :a 2 1) ;; 3
+  ((lambda (&key a b) (+ a b)) 1 :a 2) ;; error
+#+end_src
+
+So it seems, positional arguments have to be at the exact position they were
+defined in, but keyword arguments can appear in any order, but at the places
+where keyword arguments have been defined.
+
+** Idea
+
+Every argument can be set using keys, but keyword arguments always come strictly
+after positional arguments
+
+#+begin_src emacs-lisp
+  ((lambda (a b c d)) 1 2 3 4)             ;; ok
+  ((lambda (a b c d)) 1 2 :c 2 :d 1)       ;; ok
+  ((lambda (a b c d)) 1 2 :d 1 :c 2)       ;; ok
+  ((lambda (a b c d)) :d 1 1 2 :c 2)       ;; error, keyword arguments must come last
+  ((lambda (a b c d)) 1 2 :c 2 :d 1 :a 2)  ;; error, 'a' was passed two times
+
+  ((lambda (a b c d)) 1 2 :d 1)             ;; error, c was not passed, but does not have a default value
+  ((lambda (a b c :default 10 d)) 1 2 :d 1) ;; okay again
+#+end_src
+
+The drawback then is that you can never pass a keyword as a positional argument,
+because it will always try to assign the next argument to the variable defined
+by the keyword. You could still pass it as a keyword argument though. This is
+especially annoying because we want to use keywords as type identifiers.
+
+#+begin_src emacs-lisp
+(= (type "hello") :string)
+#+end_src
+
+
+#+begin_src emacs-lisp
+  ((lambda (i-wanna-get-a-kw)) :hey)                   ;; error, unmatched value for keyword argument
+  ((lambda (i-wanna-get-a-kw)) :i-wanna-get-a-kw :hey) ;; this would work again
+#+end_src
+
+Other Idea is to mark the place in the parameter list where keyword argumetns
+start and arguments before that are positional and will not be stuffed into
+key-value pairs and arguments after that will be keyword arguments
+
+#+begin_src ebnf
+<lambda list> -> <positional argument>*
+                 [:keys ( <keyword arguments> [:defaults-to <value>])*]
+                 [(:rest <rest argument>)|(:body <body argument>)]
+#+end_src
+
+#+begin_src emacs-lisp
+  (= (type "hello") :string) ;; this will work again because (=) does
+                             ;; not use keyword arguments
+  ((lambda (i-wanna-get-a-kw)) :hey) ;; would work because of the same reason
+
+  (define fun
+    (lambda (:keys a b c d)
+      (+ a b c d)))
+
+  (fun 1 2 3 4)             ;; okay
+  (fun 1 2 :d 3 :c 4)       ;; okay
+  (fun 1 2 :d 3 :c 4 :a 2)  ;; error, 'a' was passed two times
+  (fun :c 1 :b 2 :d 3 :a 4) ;; okay
+  (fun :c 1 :b 2 :d 3 4)    ;; error, positional argument after keyword
+                            ;; and fun does not accept rest parameter
+
+  (define fun2
+    (lambda (:quoted op a b :keys c d :rest r)
+      (print r)
+      (op a b c d)))
+
+>> (fun2 * 1 2 :c 3 :d 4 "this" "can" :be "whatever")
+("this" "can" :be "whatever")
+24
+
+
+>> (define print-before-eval (lambda (:body expr)
+     (print expr)
+     (eval expr)))
+>> (define r (print-before-eval (+ 1 2 3)))
+(+ 1 2 3)
+>> r
+6
+
+#+end_src
+
+Wait this does not work either because you won't be able to pass keywords into
+rest.
+
+*Unrealated Idea: Distinguish between functions and macros*
+
+The difference is really simple:
+ - Function :: like a lambda, but no argument is automatically quoted
+ - Macro :: like a lambda, but every argument is automatically quoted
+
+This is important, because a macro should not introduce a new environment, but
+use the one it lives in.
+
+#+begin_src emacs-lisp
+
+>> (define print-before-eval (macro (:rest expr)
+     (print expr)
+     (eval expr))
+
+#+end_src
+
+** the actual problem
+
+We have some requirements to the arguments:
+ - positional arguments (always required, no default value)
+ - keyword arguments (always come after positionals), can be not passed if there
+   is a default value
+ - We want to be able to have a rest paramter, where everything is dumped in to
+   that exceeds the other parameters
+
+*The problem is, we have no way of knowing if the current keyword we are
+ reading is still part of the keyword block or part of the rest paramter.*
+
+Consider:
+
+#+begin_src emacs-lisp
+  >> (define fun (lambda (a b :key c d :defaults-to 4 :rest) nil))
+  >> (fun 1 2 :c 3 :d 5)
+
+
+  (defun haha (par1 par2)
+    (+ 1 2))
+#+end_src
+What should this be evaluated to?
+
+|    | a | b | c | d | rest   |
+|----+---+---+---+---+--------|
+| v1 | 1 | 2 | 3 | 5 | nil    |
+| v2 | 1 | 2 | 3 | 4 | (:d 5) |
+
+It is ambiguous. It is however important to note that this can only happen when
+there are optinal keyword arguments (keyword arguments with default values).
+Otherwise we could always know which variables are set and wich have not been
+set to see if we are in an errornious state.
+
+** Solution
+   We can resolve that problem by always making the the decision of chosing =v1=
+   between =v1= and =v1=. This means, when we are expecting to read kwargs, and we
+   encounter an kwarg, try to apply it (this can fail, for two reasons:
+
+   1. The keyword has no following value
+   2. The keyword is not a keyword argument in the funciton
+
+   ), if it fails treat it as part of the rest arguments, and read all the
+   following arguments into the rest arguments, or if it works, use it as the
+   keyword argument.
+
+** Implementation
+
+#+begin_src c
+  typedef struct {
+      char*  docstring;
+      char** positional_arguments;
+      struct {
+          char* identifier;
+          Ast_node* default_value;    // will be nullptr if no defalut value was declared
+      }* keyword_arguments;
+      char*  rest_argument;           // will be nullptr if no rest argument is declared
+      Ast_Node_array_list body;
+  } lambda;
+#+end_src
 * TODO =assert_equal_type= macro in testing
 * DONE use an enum for builtin identifiers
   CLOSED: [2018-10-11 Do 17:15]
@@ -25,9 +218,9 @@
    CLOSED: [2018-10-05 Fr 22:21]
 ** DONE not
    CLOSED: [2018-10-05 Fr 22:21]
-#+begin_src emacs-lisp
+#+begin_src
 (not 1)                  ;; == (not . (1 . nil))
-(not (expression 1 3))   ;; == (not . ((expression . (1 . (3 . nil))) . nil))
+(not (expression 1 3))   ;; == (not . ((expression . (1 . (3 . nil))) . nil) . nil)
 (not)                    ;; == (not . nil)
 (not 1 2)                ;; == (not . (1 . (2 . nil)))
 #+end_src
@@ -62,14 +255,14 @@
 ** DONE list
    CLOSED: [2018-10-08 Mo 21:06]
 
-#+begin_src emacs-lisp
+#+begin_src
   (quote (cons 2 (cons 3 (cons 4 ()))))
   ;; (cons 2 (cons 3 (cons 4 nil)))
   (quote (2 . (3 . (4 . ()))))
   ;; (2 3 4)
 #+end_src
 
-#+begin_src emacs-lisp
+#+begin_src
   (list (cons 2 (cons 3 (cons 4 ()))))
   ;; ((2 3 4))
   (list (quote(2 . (3 . (4 . ())))))
@@ -91,16 +284,3 @@
  - pair (cons-cell)
  - lambda function lambda
  - built-in function
-
-* Arbeitsweise
-
- 1) Parse to AST
- 2) Start with namespace only containing the built-ins
- 3) every AST node has its own namespace,
-    inherting the one from its parent (pointer /
-    references) because when a function sets a
-    variable within an upper namespace it should
-    infact change the environment even if the
-    function exited
-
-(progn (setq x 4)(* x 2))

vs/slime.sln

@@ -3,7 +3,7 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
 VisualStudioVersion = 15.0.27004.2005
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "lisp", "lisp.vcxproj", "{1A47A3ED-871F-4CB4-875B-8CAA385B1771}"
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "slime", "slime.vcxproj", "{1A47A3ED-871F-4CB4-875B-8CAA385B1771}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

vs/slime.vcxproj

@@ -29,8 +29,9 @@
   <PropertyGroup Label="Globals">
     <VCProjectVersion>15.0</VCProjectVersion>
     <ProjectGuid>{1A47A3ED-871F-4CB4-875B-8CAA385B1771}</ProjectGuid>
-    <RootNamespace>lisp</RootNamespace>
+    <RootNamespace>slime</RootNamespace>
     <WindowsTargetPlatformVersion>10.0.16299.0</WindowsTargetPlatformVersion>
+    <ProjectName>slime</ProjectName>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">