Finished linked env scope on user functions.

Doesn't work for builtin functions yet, so doesn't compile. TODO.

config.mk

@@ -11,7 +11,7 @@ TEST_DIR = test
 TEST_BUILD_DIR = $(BUILD_DIR)/test
 TEST_OBJ_DIR = $(TEST_BUILD_DIR)/obj
 
-CC = clang -std=c2x
+CC = clang -std=c23
 LINK = clang
 CFLAGS = -Wall -DDBG -ggdb -fsanitize=leak
 LDFLAGS = -lm

src/ast.c

@@ -2,7 +2,7 @@
 
 #include "include/ast.h"
 #include "include/dstr.h"
-#include "include/htab.h"
+#include "include/scope.h"
 #include "include/util.h"
 
 extern AST* root;
@@ -28,7 +28,7 @@ AST* ast_init(ASTType type, void* data) {
     return ast;
 }
 
-AST* ast_init_scope(ASTType type, void* data, HTab* scope) {
+AST* ast_init_scope(ASTType type, void* data, Scope* scope) {
     AST* ast = malloc(sizeof(AST));
 
     ast->type = type;
@@ -53,8 +53,8 @@ void ast_destroy(AST* ast) {
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
 
+    scope_destroy_psv(ast->scope);
     free(ast);
-    htab_destroy(ast->scope);
 }
 
 void ast_print(AST* ast) { ast_print_i(ast, 0); }
@@ -276,3 +276,13 @@ void ast_arg_print(ASTArgData* arg, int i) {
     INDENT_FIELD("name", "%s", arg->name);
     INDENT_END;
 }
+
+AST* ast_find(Scope* scope, char* name) {
+    while (scope) {
+        AST* gotten = htab_get(scope->here, name);
+        if (gotten) return gotten;
+        else scope = scope->inherit;
+    }
+
+    return NULL;
+}

src/exec.c

@@ -6,67 +6,58 @@
 #include "include/builtin.h"
 #include "include/exec.h"
 #include "include/htab.h"
-#include "include/stack.h"
+#include "include/scope.h"
 #include "include/util.h"
 
-extern AST* root;
-
-AST* exec_find(char* name);
-
 AST* exec_start(AST* ast) {
     log_dbg("Started execution.");
-    scope = stack_init();
 
-    HTab* global = htab_init();
+    Scope* builtin = scope_init(NULL);
 
     for (int i = 0; i < BUILTIN_FNS_LN; i++)
         htab_ins(
-            global, BUILTIN_FNS[i].name,
+            builtin->here, BUILTIN_FNS[i].name,
             ast_init(AST_TYPE_BIF, ast_bif_data_init(BUILTIN_FNS[i].fn))
         );
 
-    // Push global namespace to `scope`.
-    stack_push(scope, global);
-
-    return exec_exp(ast);
+    return exec_exp(ast, builtin);
 }
 
-AST* exec_exp(AST* ast) {
+AST* exec_exp(AST* ast, Scope* parent) {
     switch (ast->type) {
-        case AST_TYPE_BLOCK: return exec_block(ast);
-        case AST_TYPE_CALL:  return exec_call(ast);
+        case AST_TYPE_BLOCK: return exec_block(ast, parent);
+        case AST_TYPE_CALL:  return exec_call(ast, parent);
         case AST_TYPE_NUM:   return ast;
-        case AST_TYPE_VREF:  return exec_vref(ast);
-        case AST_TYPE_VDEF:  return exec_vdef(ast);
-        case AST_TYPE_FDEF:  return exec_fdef(ast);
+        case AST_TYPE_VREF:  return exec_vref(ast, parent);
+        case AST_TYPE_VDEF:  return exec_vdef(ast, parent);
+        case AST_TYPE_FDEF:  return exec_fdef(ast, parent);
         default:             printf("what\n"); exit(1);
     }
 }
 
-AST* exec_block(AST* ast) {
+AST* exec_block(AST* ast, Scope* parent) {
     ASTBlockData* block = (ASTBlockData*)ast->data;
 
-    HTab* local = htab_init();
-    stack_push(scope, local);
+    ast->scope = scope_init(parent);
 
     // Loop through all but last ast.
-    for (int i = 0; i < block->ln - 1; i++) exec_exp(block->inside[i]);
-    AST* last = exec_exp(block->inside[block->ln - 1]);
-
-    stack_pop(scope);
-    htab_destroy(local);
+    for (int i = 0; i < block->ln - 1; i++)
+        exec_exp(block->inside[i], ast->scope);
+    AST* last = exec_exp(block->inside[block->ln - 1], ast->scope);
 
     return last;
 }
 
-AST* exec_call(AST* ast) {
+AST* exec_call(AST* ast, Scope* parent) {
     log_dbg("Started call execution.");
     ASTCallData* data = (ASTCallData*)ast->data;
     size_t argc = data->argc;
     AST** argv = data->argv;
     char* fname = data->to;
 
-    AST* fdef = exec_find(fname);
+    ast->scope = parent;
+
+    AST* fdef = ast_find(ast->scope, fname);
 
     if (fdef == NULL)
         return ast_init(
@@ -84,41 +75,32 @@ AST* exec_call(AST* ast) {
 }
 
 AST* exec_cf(AST* ast, size_t argc, AST** argv) {
+    Scope* callscope = scope_init(ast->scope);
     ASTFDefData* fdef = (ASTFDefData*)ast->data;
     for (int i = 0; i < argc; i++) {
         char* key = ((ASTArgData*)fdef->argv[i]->data)->name;
         AST* val = argv[i];
-        htab_ins(scope->buf[scope->ln - 1], key, val);
+        scope_add(callscope, key, val);
     }
 
-    return exec_exp(fdef->body);
+    return exec_exp(fdef->body, callscope);
 }
 
-AST* exec_find(char* name) {
-    AST* val = NULL;
-
-    for (int i = scope->ln - 1; i >= 0; i--) {
-        HTab* lvl = scope->buf[i];
-        val = htab_get(lvl, name);
-        if (val != NULL) return val;
-    }
-
-    return NULL;
-}
-
-AST* exec_vdef(AST* ast) {
+AST* exec_vdef(AST* ast, Scope* parent) {
+    ast->scope = scope_init(parent);
     ASTVDefData* data = (ASTVDefData*)ast->data;
     AST* val = data->val;
     char* key = data->name;
-    htab_ins(scope->buf[scope->ln - 1], key, val);
-    return exec_exp(val);
+    scope_add(parent, key, val);
+    return exec_exp(val, ast->scope);
 }
 
-AST* exec_vref(AST* ast) {
+AST* exec_vref(AST* ast, Scope* parent) {
+    ast->scope = parent;
     log_dbg("attempting to reference var");
     ASTVrefData* vref = (ASTVrefData*)ast->data;
 
-    AST* found = exec_find(vref->to);
+    AST* found = ast_find(parent, vref->to);
 
     if (found == NULL) {
         // TODO: Better memory management here.
@@ -130,14 +112,15 @@ AST* exec_vref(AST* ast) {
         return ast_init(AST_TYPE_EXC, ast_exc_data_init(msg, NULL));
     }
 
-    return exec_exp(found);
+    return exec_exp(found, ast->scope);
 }
 
-AST* exec_fdef(AST* ast) {
+AST* exec_fdef(AST* ast, Scope* parent) {
+    ast->scope = scope_init(parent);
     ASTFDefData* fdef = (ASTFDefData*)ast->data;
     AST* val = fdef->body;
     char* key = fdef->name;
-    htab_ins(scope->buf[scope->ln - 1], key, val);
+    scope_add(parent, key, val);
     return val; // Function definitions return function body.
 }
 

src/include/ast.h

@@ -1,7 +1,7 @@
 #ifndef AST_H
 #define AST_H
 
-#include "htab.h"
+#include "scope.h"
 #include <stdlib.h>
 
 // The type of an `AST`.
@@ -32,13 +32,13 @@ typedef enum {
 typedef struct {
     ASTType type; // The type of the `AST`.
     void* data;   // The data of the `AST`.
-    HTab* scope;  // The scope of the `AST`.
+    Scope* scope; // The scope of the `AST`.
 } AST;
 
 // Create a new `AST`.
 AST* ast_init(ASTType type, void* data);
 // Create a new `AST` with a specified scope.
-AST* ast_init_scope(ASTType type, void* data, HTab* scope);
+AST* ast_init_scope(ASTType type, void* data, Scope* scope);
 // Destroy an `AST`, recursively.
 void ast_destroy(AST* ast);
 // Print an `AST`, recursively.
@@ -153,4 +153,7 @@ void ast_arg_data_destroy(ASTArgData* arg);
 // Print an `ASTArgData`.
 void ast_arg_print(ASTArgData* arg, int i);
 
+// Find a name in the scope.
+AST* ast_find(Scope* scope, char* name);
+
 #endif

src/include/exec.h

@@ -2,27 +2,24 @@
 #define EXEC_H
 
 #include "ast.h"
-#include "stack.h"
-
-// The `Stack` of `HTab` that makes up the scope of any given `AST`.
-extern Stack* scope;
+#include "scope.h"
 
 // Start executing at the root of the AST. Initialize the `scope`.
 AST* exec_start(AST* ast);
 // Execute an expression. Delegates to the other executor functions.
-AST* exec_exp(AST* ast);
+AST* exec_exp(AST* ast, Scope* parent);
 // Execute the expressions of a block.
-AST* exec_block(AST* ast);
+AST* exec_block(AST* ast, Scope* parent);
 // Execute a call.
-AST* exec_call(AST* ast);
+AST* exec_call(AST* ast, Scope* parent);
 // Execute a custom function call.
 AST* exec_cf(AST* ast, size_t argc, AST** argv);
-// Execute a variable reference.
-AST* exec_vref(AST* ast);
 // Execute a variable definition.
-AST* exec_vdef(AST* ast);
+AST* exec_vdef(AST* ast, Scope* parent);
+// Execute a variable reference.
+AST* exec_vref(AST* ast, Scope* parent);
 // Execute a function definition.
-AST* exec_fdef(AST* ast);
+AST* exec_fdef(AST* ast, Scope* parent);
 // Print the result of an execution.
 void exec_print(double n);
 

src/include/scope.h

@@ -0,0 +1,21 @@
+#ifndef SCOPE_H
+#define SCOPE_H
+
+#include "htab.h"
+
+// Represents the reverse linked tree of scope.
+typedef struct SCOPE_T {
+    HTab* here;
+    struct SCOPE_T* inherit;
+} Scope;
+
+// Create a new `Scope`. Creates new empty `HTab` for current scope.
+Scope* scope_init(Scope* inherit);
+// Destroy all linked `Scope`s this inherits from.
+void scope_destroy(Scope* scope);
+// Destroy the current `Scope` only.
+void scope_destroy_psv(Scope *scope);
+// Insert a key/val pair into the `HTab` of a `Scope`.
+inline void scope_add(Scope* scope, char* key, void* val);
+
+#endif

src/scope.c

@@ -0,0 +1,28 @@
+#include "include/scope.h"
+#include "include/htab.h"
+#include <stdlib.h>
+
+Scope* scope_init(Scope* inherit) {
+    Scope* scope = malloc(sizeof(Scope));
+
+    scope->here = htab_init();
+    scope->inherit = inherit;
+
+    return scope;
+}
+
+void scope_destroy(Scope* scope) {
+    htab_destroy(scope->here);
+    if (scope->inherit != NULL) scope_destroy(scope->inherit);
+    free(scope);
+}
+
+void scope_destroy_psv(Scope* scope) {
+    htab_destroy(scope->here);
+    scope->inherit = NULL;
+    free(scope);
+}
+
+inline void scope_add(Scope* scope, char* key, void* val) {
+    htab_ins(scope->here, key, val);
+}

test/Unity

@@ -1 +1 @@
-Subproject commit cdf1d0297effc2736ee847e557b4275b4f02310b
+Subproject commit 73237c5d224169c7b4d2ec8321f9ac92e8071708