Add delete keyword to delete variables and object items

Voxellius · Jul 16, 2024 · e06681b · e06681b
1 parent 04d1b71
commit e06681b
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Showing 11 changed files with 175 additions and 11 deletions.
diff --git a/dist/libvoxel.h b/dist/libvoxel.h
@@ -335,6 +335,7 @@ typedef enum voxel_TokenType {
     VOXEL_TOKEN_TYPE_GET = '?',
     VOXEL_TOKEN_TYPE_SET = ':',
     VOXEL_TOKEN_TYPE_VAR = 'v',
+    VOXEL_TOKEN_TYPE_DELETE = 'D',
     VOXEL_TOKEN_TYPE_POP = 'p',
     VOXEL_TOKEN_TYPE_DUPE = 'd',
     VOXEL_TOKEN_TYPE_OVER = 'o',
@@ -567,6 +568,7 @@ VOXEL_ERRORABLE voxel_destroyScope(voxel_Scope* scope);
 voxel_ObjectItem* voxel_getScopeItem(voxel_Scope* scope, voxel_Thing* key);
 VOXEL_ERRORABLE voxel_setScopeItem(voxel_Scope* scope, voxel_Thing* key, voxel_Thing* value);
 VOXEL_ERRORABLE voxel_setLocalScopeItem(voxel_Scope* scope, voxel_Thing* key, voxel_Thing* value);
+VOXEL_ERRORABLE voxel_removeScopeItem(voxel_Scope* scope, voxel_Thing* key);
 
 voxel_Executor* voxel_newExecutor(voxel_Context* context);
 voxel_Executor* voxel_cloneExecutor(voxel_Executor* executor, voxel_Bool copyValueStack);
@@ -1343,12 +1345,10 @@ void voxel_builtins_core_removeObjectItem(voxel_Executor* executor) {
     voxel_Thing* key = voxel_pop(executor);
     voxel_Thing* object = voxel_pop(executor);
 
-    if (!object || object->type != VOXEL_TYPE_OBJECT || object->isLocked || argCount < 2) {
-        return voxel_pushNull(executor);
+    if (object && object->type == VOXEL_TYPE_OBJECT && !object->isLocked && argCount >= 2) {
+        voxel_removeObjectItem(executor->context, object, key);
     }
 
-    voxel_removeObjectItem(executor->context, object, key);
-
     voxel_unreferenceThing(executor->context, key);
     voxel_unreferenceThing(executor->context, object);
 
@@ -5030,6 +5030,7 @@ VOXEL_ERRORABLE voxel_nextToken(voxel_Executor* executor, voxel_Position* positi
         case VOXEL_TOKEN_TYPE_GET:
         case VOXEL_TOKEN_TYPE_SET:
         case VOXEL_TOKEN_TYPE_VAR:
+        case VOXEL_TOKEN_TYPE_DELETE:
         case VOXEL_TOKEN_TYPE_POP:
         case VOXEL_TOKEN_TYPE_DUPE:
         case VOXEL_TOKEN_TYPE_OVER:
@@ -5358,7 +5359,9 @@ VOXEL_ERRORABLE voxel_stepExecutor(voxel_Executor* executor) {
             VOXEL_MUST(voxel_pushOntoList(executor->context, executor->valueStack, scopeValue));
             VOXEL_MUST(voxel_unreferenceThing(executor->context, (voxel_Thing*)getKey.value));
 
-            scopeValue->referenceCount++; // To ensure that builtins don't dereference the thing in the scope
+            if (scopeItem) {
+                scopeValue->referenceCount++; // To ensure that builtins don't dereference the thing in the scope
+            }
 
             break;
         }
@@ -5378,6 +5381,18 @@ VOXEL_ERRORABLE voxel_stepExecutor(voxel_Executor* executor) {
             break;
         }
 
+        case VOXEL_TOKEN_TYPE_DELETE:
+        {
+            VOXEL_ERRORABLE deleteKey = voxel_popFromList(executor->context, executor->valueStack); VOXEL_MUST(deleteKey);
+
+            VOXEL_ASSERT(deleteKey.value, VOXEL_ERROR_MISSING_ARG);
+
+            VOXEL_MUST(voxel_removeScopeItem(executor->scope, (voxel_Thing*)deleteKey.value));
+            VOXEL_MUST(voxel_unreferenceThing(executor->context, (voxel_Thing*)deleteKey.value));
+
+            break;
+        }
+
         case VOXEL_TOKEN_TYPE_POP:
         {
             VOXEL_ERRORABLE popResult = voxel_popFromList(executor->context, executor->valueStack); VOXEL_MUST(popResult);
@@ -5758,6 +5773,20 @@ VOXEL_ERRORABLE voxel_setLocalScopeItem(voxel_Scope* scope, voxel_Thing* key, vo
     return voxel_setObjectItem(scope->context, scope->things, key, value);
 }
 
+VOXEL_ERRORABLE voxel_removeScopeItem(voxel_Scope* scope, voxel_Thing* key) {
+    voxel_ObjectItem* thisScopeItem = voxel_getObjectItem(scope->things, key);
+
+    if (thisScopeItem) {
+        return voxel_removeObjectItem(scope->context, scope->things, key);
+    }
+
+    if (scope->parentScope) {
+        return voxel_removeScopeItem(scope->context->globalScope, key);
+    }
+
+    return VOXEL_OK;
+}
+
 // src/helpers.h
 
 #define _VOXEL_HELPER_POP_VALUE(name, type, popCall, getValueCall, defaultValue) type name(voxel_Executor* executor) { \

diff --git a/src/builtins/core/objects.h b/src/builtins/core/objects.h
@@ -59,12 +59,10 @@ void voxel_builtins_core_removeObjectItem(voxel_Executor* executor) {
     voxel_Thing* key = voxel_pop(executor);
     voxel_Thing* object = voxel_pop(executor);
 
-    if (!object || object->type != VOXEL_TYPE_OBJECT || object->isLocked || argCount < 2) {
-        return voxel_pushNull(executor);
+    if (object && object->type == VOXEL_TYPE_OBJECT && !object->isLocked && argCount >= 2) {
+        voxel_removeObjectItem(executor->context, object, key);
     }
 
-    voxel_removeObjectItem(executor->context, object, key);
-
     voxel_unreferenceThing(executor->context, key);
     voxel_unreferenceThing(executor->context, object);
 

diff --git a/src/declarations.h b/src/declarations.h
@@ -140,6 +140,7 @@ typedef enum voxel_TokenType {
     VOXEL_TOKEN_TYPE_GET = '?',
     VOXEL_TOKEN_TYPE_SET = ':',
     VOXEL_TOKEN_TYPE_VAR = 'v',
+    VOXEL_TOKEN_TYPE_DELETE = 'D',
     VOXEL_TOKEN_TYPE_POP = 'p',
     VOXEL_TOKEN_TYPE_DUPE = 'd',
     VOXEL_TOKEN_TYPE_OVER = 'o',
@@ -372,6 +373,7 @@ VOXEL_ERRORABLE voxel_destroyScope(voxel_Scope* scope);
 voxel_ObjectItem* voxel_getScopeItem(voxel_Scope* scope, voxel_Thing* key);
 VOXEL_ERRORABLE voxel_setScopeItem(voxel_Scope* scope, voxel_Thing* key, voxel_Thing* value);
 VOXEL_ERRORABLE voxel_setLocalScopeItem(voxel_Scope* scope, voxel_Thing* key, voxel_Thing* value);
+VOXEL_ERRORABLE voxel_removeScopeItem(voxel_Scope* scope, voxel_Thing* key);
 
 voxel_Executor* voxel_newExecutor(voxel_Context* context);
 voxel_Executor* voxel_cloneExecutor(voxel_Executor* executor, voxel_Bool copyValueStack);

diff --git a/src/executors.h b/src/executors.h
@@ -260,7 +260,9 @@ VOXEL_ERRORABLE voxel_stepExecutor(voxel_Executor* executor) {
             VOXEL_MUST(voxel_pushOntoList(executor->context, executor->valueStack, scopeValue));
             VOXEL_MUST(voxel_unreferenceThing(executor->context, (voxel_Thing*)getKey.value));
 
-            scopeValue->referenceCount++; // To ensure that builtins don't dereference the thing in the scope
+            if (scopeItem) {
+                scopeValue->referenceCount++; // To ensure that builtins don't dereference the thing in the scope
+            }
 
             break;
         }
@@ -280,6 +282,18 @@ VOXEL_ERRORABLE voxel_stepExecutor(voxel_Executor* executor) {
             break;
         }
 
+        case VOXEL_TOKEN_TYPE_DELETE:
+        {
+            VOXEL_ERRORABLE deleteKey = voxel_popFromList(executor->context, executor->valueStack); VOXEL_MUST(deleteKey);
+
+            VOXEL_ASSERT(deleteKey.value, VOXEL_ERROR_MISSING_ARG);
+
+            VOXEL_MUST(voxel_removeScopeItem(executor->scope, (voxel_Thing*)deleteKey.value));
+            VOXEL_MUST(voxel_unreferenceThing(executor->context, (voxel_Thing*)deleteKey.value));
+
+            break;
+        }
+
         case VOXEL_TOKEN_TYPE_POP:
         {
             VOXEL_ERRORABLE popResult = voxel_popFromList(executor->context, executor->valueStack); VOXEL_MUST(popResult);

diff --git a/src/parser.h b/src/parser.h
@@ -204,6 +204,7 @@ VOXEL_ERRORABLE voxel_nextToken(voxel_Executor* executor, voxel_Position* positi
         case VOXEL_TOKEN_TYPE_GET:
         case VOXEL_TOKEN_TYPE_SET:
         case VOXEL_TOKEN_TYPE_VAR:
+        case VOXEL_TOKEN_TYPE_DELETE:
         case VOXEL_TOKEN_TYPE_POP:
         case VOXEL_TOKEN_TYPE_DUPE:
         case VOXEL_TOKEN_TYPE_OVER:

diff --git a/src/scopes.h b/src/scopes.h
@@ -47,4 +47,18 @@ VOXEL_ERRORABLE voxel_setScopeItem(voxel_Scope* scope, voxel_Thing* key, voxel_T
 
 VOXEL_ERRORABLE voxel_setLocalScopeItem(voxel_Scope* scope, voxel_Thing* key, voxel_Thing* value) {
     return voxel_setObjectItem(scope->context, scope->things, key, value);
+}
+
+VOXEL_ERRORABLE voxel_removeScopeItem(voxel_Scope* scope, voxel_Thing* key) {
+    voxel_ObjectItem* thisScopeItem = voxel_getObjectItem(scope->things, key);
+
+    if (thisScopeItem) {
+        return voxel_removeObjectItem(scope->context, scope->things, key);
+    }
+
+    if (scope->parentScope) {
+        return voxel_removeScopeItem(scope->context->globalScope, key);
+    }
+
+    return VOXEL_OK;
 }
diff --git a/test/delete/expected.log b/test/delete/expected.log
@@ -0,0 +1,8 @@
+Before deletion: hello
+After deletion: null
+Before index accessor deletion: value1
+After index accessor deletion: null
+Attempt deletion of non-object index accessor: null
+Before property accessor deletion: value2
+After property accessor deletion: null
+Attempt deletion of non-object property accessor: null
diff --git a/test/delete/main.vxl b/test/delete/main.vxl
@@ -0,0 +1,44 @@
+var value = "hello";
+
+syscall io_out("Before deletion: ");
+syscall io_out(value);
+syscall io_out("\n");
+
+delete value;
+
+syscall io_out("After deletion: ");
+syscall io_out(value);
+syscall io_out("\n");
+
+var object = {
+    "key": "value1",
+    prop: "value2"
+};
+
+syscall io_out("Before index accessor deletion: ");
+syscall io_out(object["key"]);
+syscall io_out("\n");
+
+delete object["key"];
+
+syscall io_out("After index accessor deletion: ");
+syscall io_out(object["key"]);
+syscall io_out("\n");
+
+syscall io_out("Attempt deletion of non-object index accessor: ");
+syscall io_out(value["key"]);
+syscall io_out("\n");
+
+syscall io_out("Before property accessor deletion: ");
+syscall io_out(object.prop);
+syscall io_out("\n");
+
+delete object.prop;
+
+syscall io_out("After property accessor deletion: ");
+syscall io_out(object.prop);
+syscall io_out("\n");
+
+syscall io_out("Attempt deletion of non-object property accessor: ");
+syscall io_out(value.prop);
+syscall io_out("\n");
diff --git a/tools/vxbuild-js/codegen.js b/tools/vxbuild-js/codegen.js
@@ -20,6 +20,7 @@ export const vxcTokens = {
     GET: byte("?"),
     SET: byte(":"),
     VAR: byte("v"),
+    DELETE: byte("D"),
     POP: byte("p"),
     DUPE: byte("d"),
     OVER: byte("o"),

diff --git a/tools/vxbuild-js/statements.js b/tools/vxbuild-js/statements.js
@@ -30,6 +30,7 @@ export class StatementNode extends ast.AstNode {
             EnumStatementNode,
             BreakStatementNode,
             ContinueStatementNode,
+            DeleteStatementNode,
             expressions.ExpressionNode
         ], namespace);
 
@@ -720,4 +721,56 @@ export class ContinueStatementNode extends ast.AstNode {
             codeGen.bytes(codeGen.vxcTokens.GET, codeGen.vxcTokens.JUMP)
         );
     }
+}
+
+export class DeleteStatementNode extends ast.AstNode {
+    static HUMAN_READABLE_NAME = "`delete` statement";
+
+    static MATCH_QUERIES = [
+        new ast.TokenQuery(tokeniser.KeywordToken, "delete")
+    ];
+
+    keywordToken = null;
+
+    static create(tokens, namespace) {
+        var instance = new this();
+
+        instance.keywordToken = this.eat(tokens);
+
+        instance.expectChildByMatching(tokens, [expressions.ExpressionThingNode], namespace);
+
+        return instance;
+    }
+
+    generateCode(options) {
+        var targetInstance = this.children[0];
+        var target = targetInstance.children.at(-1);
+
+        if (target instanceof expressions.FunctionCallNode) {
+            throw new sources.SourceError("Expected an identifier (cannot delete the return value of a function)", this.keywordToken?.sourceContainer, this.keywordToken?.location);
+        }
+
+        if (target instanceof expressions.IndexAccessorNode || target instanceof expressions.PropertyAccessorNode) {
+            var accessor = targetInstance.children.pop();
+
+            return codeGen.join(
+                targetInstance.generateCode(options),
+                target instanceof expressions.PropertyAccessorNode ? accessor.propertySymbol.generateCode(options) : accessor.children[0].generateCode(options),
+                codeGen.number(2),
+                codeGen.systemCall("Or"),
+                codeGen.bytes(codeGen.vxcTokens.POP)
+            );
+        }
+
+        if (target instanceof expressions.ThingNode) {
+            if (target.value instanceof namespaces.Symbol) {
+                return codeGen.join(
+                    target.value.generateCode(options),
+                    codeGen.bytes(codeGen.vxcTokens.DELETE)
+                );
+            }
+        }
+
+        throw new sources.SourceError("Expected an identifier", this.keywordToken?.sourceContainer, this.keywordToken?.location);
+    }
 }
diff --git a/tools/vxbuild-js/tokeniser.js b/tools/vxbuild-js/tokeniser.js
@@ -174,7 +174,7 @@ export function tokenise(sourceContainer) {
             continue;
         }
 
-        if (matchToken(/^(?:syscall|import|as|return|function|class|extends|get|set|this|super|new|var|if|else|while|for|retain|throw|try|catch|enum|break|continue)\b/)) {
+        if (matchToken(/^(?:syscall|import|as|return|function|class|extends|get|set|this|super|new|var|if|else|while|for|retain|throw|try|catch|enum|break|continue|delete)\b/)) {
             addToken(KeywordToken);
             continue;
         }