refactor: special forms
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@@ -1,6 +1,19 @@
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#include "lisp.h"
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static Scope global_scope = {0};
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static LispFunction special_forms[] = {
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{
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.name = (Nob_String_View){.count = 2, .data = "if"},
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.apply = special_form_if,
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},
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{.name = (Nob_String_View){.count = 6, .data = "define"},
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.apply = special_form_define},
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{.name = (Nob_String_View){.count = 3, .data = "let"},
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.apply = special_form_let},
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{
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.name = (Nob_String_View){.count = 6, .data = "lambda"},
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.apply = special_form_lambda,
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}};
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static int scope_lookup(Scopes *scopes, Nob_String_View name, Node *result) {
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nob_da_foreach(Scope *, scope, scopes) {
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@@ -17,7 +30,7 @@ static int scope_lookup(Scopes *scopes, Nob_String_View name, Node *result) {
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}
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static void scope_add_function(Scope *scope, const char *name,
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LispFunction function) {
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LispFunctionPtr function) {
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Nob_String_View obj_name = nob_sv_from_cstr(name);
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ScopeObject obj = (ScopeObject){
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.name = obj_name,
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@@ -26,37 +39,26 @@ static void scope_add_function(Scope *scope, const char *name,
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nob_da_append(scope, obj);
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}
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static bool node_is_true(Node node) {
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switch (node.kind) {
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case NODE_KIND_NUMBER:
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return node.as_number != 0;
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case NODE_KIND_LIST:
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return node.as_list->count > 0;
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default:
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return true;
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}
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}
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void build_scopes(Scopes *scopes) {
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scope_add_function(&global_scope, "+", lisp_function_add);
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scope_add_function(&global_scope, "-", lisp_function_sub);
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scope_add_function(&global_scope, "/", lisp_function_div);
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scope_add_function(&global_scope, "*", lisp_function_mul);
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scope_add_function(&global_scope, "=", lisp_function_eq);
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scope_add_function(&global_scope, "<", lisp_function_lt);
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scope_add_function(&global_scope, ">", lisp_function_gt);
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scope_add_function(&global_scope, "<=", lisp_function_lt_eq);
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scope_add_function(&global_scope, ">=", lisp_function_gt_eq);
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scope_add_function(&global_scope, "+", builtin_add);
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scope_add_function(&global_scope, "-", builtin_sub);
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scope_add_function(&global_scope, "/", builtin_div);
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scope_add_function(&global_scope, "*", builtin_mul);
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scope_add_function(&global_scope, "=", builtin_eq);
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scope_add_function(&global_scope, "<", builtin_lt);
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scope_add_function(&global_scope, ">", builtin_gt);
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scope_add_function(&global_scope, "<=", builtin_lt_eq);
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scope_add_function(&global_scope, ">=", builtin_gt_eq);
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scope_add_function(&global_scope, "println", lisp_function_println);
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scope_add_function(&global_scope, "list", lisp_function_list);
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scope_add_function(&global_scope, "append", lisp_function_append);
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scope_add_function(&global_scope, "length", lisp_function_length);
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scope_add_function(&global_scope, "null?", lisp_function_isnull);
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scope_add_function(&global_scope, "builtins", lisp_function_builtins);
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scope_add_function(&global_scope, "println", builtin_println);
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scope_add_function(&global_scope, "list", builtin_list);
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scope_add_function(&global_scope, "append", builtin_append);
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scope_add_function(&global_scope, "length", builtin_length);
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scope_add_function(&global_scope, "null?", builtin_isnull);
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scope_add_function(&global_scope, "builtins", builtin_builtins);
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scope_add_function(&global_scope, "floor", lisp_function_floor);
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scope_add_function(&global_scope, "ceil", lisp_function_ceil);
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scope_add_function(&global_scope, "floor", builtin_floor);
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scope_add_function(&global_scope, "ceil", builtin_ceil);
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nob_da_append(scopes, &global_scope);
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}
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@@ -305,168 +307,16 @@ int eval_one(Node input, Scopes *scopes, Node *result) {
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Node head_node = children->items[0];
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if (head_node.kind == NODE_KIND_SYMBOL) {
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if (nob_sv_eq(head_node.as_symbol,
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(Nob_String_View){.count = 2, .data = "if"})) {
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if (children->count != 3 + 1) {
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printf("'if' expects three arguments!\n");
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return 1;
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}
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Node condition = {0};
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int ret = eval_one(children->items[0 + 1], scopes, &condition);
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if (ret != 0) {
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return ret;
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}
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if (node_is_true(condition)) {
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ret = eval_one(children->items[1 + 1], scopes, result);
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} else {
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ret = eval_one(children->items[2 + 1], scopes, result);
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}
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return ret;
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}
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if (nob_sv_eq(head_node.as_symbol,
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(Nob_String_View){.count = 6, .data = "define"})) {
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if (children->count != 2 + 1) {
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printf("'define' expects two arguments!\n");
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return 1;
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}
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Node name_node = children->items[0 + 1];
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if (name_node.kind != NODE_KIND_SYMBOL) {
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printf("First argument of 'define' must be a symbol!\n");
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return 1;
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}
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Node value = {0};
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int ret = eval_one(children->items[1 + 1], scopes, &value);
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if (ret != 0) {
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return ret;
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}
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nob_da_foreach(ScopeObject, scope_object, &global_scope) {
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if (nob_sv_eq(scope_object->name, name_node.as_symbol)) {
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scope_object->node = value;
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*result = children->items[0 + 1];
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return 0;
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}
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}
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ScopeObject obj =
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(ScopeObject){.name = name_node.as_symbol, .node = value};
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nob_da_append(&global_scope, obj);
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*result = children->items[0 + 1];
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return 0;
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}
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if (nob_sv_eq(head_node.as_symbol,
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(Nob_String_View){.count = 3, .data = "let"})) {
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if (children->count != 2 + 1) {
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printf("'let' expects two arguments!\n");
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return 1;
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}
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Node definitions = children->items[0 + 1];
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if (definitions.kind != NODE_KIND_LIST) {
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printf("First argument of 'let' must be a list!\n");
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return 1;
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}
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Node expression = children->items[1 + 1];
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if (expression.kind != NODE_KIND_LIST) {
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printf("Second argument of 'let' must be a list!\n");
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return 1;
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}
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// it's fine to allocate this on the stack because we will throw
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// it off the scope stack after parsing 'let' anyways therefore
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// it'll outlive the recursive call
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Scope scope = {0};
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nob_da_foreach(Node, def, definitions.as_list) {
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if (def->kind != NODE_KIND_LIST ||
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def->as_list->count != 2 ||
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def->as_list->items[0].kind != NODE_KIND_SYMBOL) {
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printf("'let' expects a list of key-value pairs, e.g. "
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"'(let ((x 42) (y 2)) (+ x y))'\n");
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return 1;
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}
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Node key = def->as_list->items[0];
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Node value_node = def->as_list->items[1];
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Node value = {0};
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int ret = eval_one(value_node, scopes, &value);
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for (size_t i = 0; i < NOB_ARRAY_LEN(special_forms); i++) {
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LispFunction special_form = special_forms[i];
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if (nob_sv_eq(head_node.as_symbol, special_form.name)) {
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Nodes args = {.count = children->count - 1,
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.items = children->items + 1};
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int ret = special_form.apply(args, scopes, result);
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if (ret != 0)
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return ret;
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ScopeObject obj =
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(ScopeObject){.name = key.as_symbol, .node = value};
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nob_da_append(&scope, obj);
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}
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Node expression_value = {0};
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{
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nob_da_append(scopes, &scope);
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int ret = eval_one(expression, scopes, &expression_value);
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if (ret != 0) {
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return ret;
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}
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UNUSED(nob_da_pop(scopes));
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}
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*result = expression_value;
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return 0;
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}
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if (nob_sv_eq(head_node.as_symbol,
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(Nob_String_View){.count = 6, .data = "lambda"})) {
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if (children->count != 2 + 1) {
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printf("'lambda' expects two argument!\n");
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return 1;
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}
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Node params = children->items[0 + 1];
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if (params.kind != NODE_KIND_LIST) {
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printf("'lambda' expects a list of parameters as the first "
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"argument!\n");
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return 1;
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}
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nob_da_foreach(Node, node, params.as_list) {
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if (node->kind != NODE_KIND_SYMBOL) {
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printf("'lambda' expects a list of symbols "
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"(parameters) as "
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"the "
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"first argument!\n");
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return 1;
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}
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return 0;
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}
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result->kind = NODE_KIND_LAMBDA;
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Nodes *params_list = malloc(sizeof(Nodes));
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if (params_list == NULL) {
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printf("Failed to allocate memory, something is really "
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"wrong!\n");
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return 1;
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}
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memcpy(params_list, params.as_list, sizeof(Nodes));
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result->as_lambda.params = params_list;
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Node *body = malloc(sizeof(Node));
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if (body == NULL) {
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printf("Failed to allocate memory, something is really "
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"wrong!\n");
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return 1;
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}
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memcpy(body, &children->items[1 + 1], sizeof(Node));
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result->as_lambda.body = body;
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return 0;
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}
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}
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