feat: lambda functions
This commit is contained in:
@@ -100,6 +100,9 @@ void node_print(Node node) {
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Nob_String_View func_name = node.as_function.name;
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printf(SV_Fmt, SV_Arg(func_name));
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} break;
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case NODE_KIND_LAMBDA: {
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printf("<lambda>");
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} break;
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default:
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UNREACHABLE("Unknown node type");
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}
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@@ -300,125 +303,177 @@ int eval_one(Node input, Scopes *scopes, Node *result) {
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return 0;
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}
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Node head = children->items[0];
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if (head.kind != NODE_KIND_SYMBOL) {
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*result = input;
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return 0;
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}
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if (nob_sv_eq(head.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.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.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 it
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// off the scope stack after parsing 'let' anyways therefore it'll
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// 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 || 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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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 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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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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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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UNUSED(nob_da_pop(scopes));
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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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*result = expression_value;
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return 0;
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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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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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}
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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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Node head = {0};
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int ret = eval_one(head_node, scopes, &head);
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if (ret != 0) {
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return ret;
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}
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Nodes args = {0};
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@@ -431,22 +486,69 @@ int eval_one(Node input, Scopes *scopes, Node *result) {
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nob_da_append(&args, n);
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}
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Node func_node = {0};
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int ret = eval_one(head, scopes, &func_node);
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if (ret != 0) {
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return ret;
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}
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if (func_node.kind == NODE_KIND_FUNCTION) {
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func_node.as_function.apply(args, scopes, result);
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switch (head.kind) {
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case NODE_KIND_FUNCTION: {
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head.as_function.apply(args, scopes, result);
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return 0;
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}
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case NODE_KIND_LAMBDA: {
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Nodes *lambda_params = head.as_lambda.params;
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if (lambda_params == NULL) {
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printf("Couldn't evaluate lambda, no params!\n");
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return 1;
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}
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printf("Not a function: '");
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node_print(func_node);
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printf("'\n");
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return 1;
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if (lambda_params->count != args.count) {
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printf("Invalid amount of arguments to lambda: expected %zu, "
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"found %zu\n!",
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lambda_params->count, args.count);
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return 1;
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}
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Node *lambda_body = head.as_lambda.body;
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if (lambda_body == NULL) {
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printf("Couldn't evaluate lambda, no body!\n");
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return 1;
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}
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Scope scope = {0};
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// params->count == args.count
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for (size_t i = 0; i < lambda_params->count; i++) {
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Node param = lambda_params->items[i];
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// this should already be checked when we emit the lambda node
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NOB_ASSERT(param.kind == NODE_KIND_SYMBOL);
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Node value = args.items[i];
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ScopeObject obj = {.name = param.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(*lambda_body, 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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} break;
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default: {
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printf("Not a function-like object: '");
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node_print(head);
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printf("'\n");
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return 1;
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}
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}
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}
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case NODE_KIND_LAMBDA: {
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return 0;
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} break;
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default:
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return 1;
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}
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@@ -26,6 +26,7 @@ typedef enum e_NodeKind {
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NODE_KIND_LIST,
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NODE_KIND_NUMBER,
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NODE_KIND_FUNCTION,
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NODE_KIND_LAMBDA,
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} NodeKind;
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typedef struct s_Node Node;
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@@ -46,6 +47,10 @@ struct s_Node {
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Nob_String_View name;
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LispFunction apply;
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} as_function;
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struct {
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Nodes *params;
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Node *body;
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} as_lambda;
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};
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};
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