Custom Procedures: Substacks (VM)

src/blocks/scratch3_procedures.js

@@ -16,6 +16,7 @@
             procedures_definition: this.definition,
             procedures_call: this.call,
             procedures_return: this.return,
+            argument_statement: this.argumentStatement,
             argument_reporter_string_number: this.argumentReporterStringNumber,
             argument_reporter_boolean: this.argumentReporterBoolean
         };
@@ -65,6 +66,11 @@
         for (let i = 0; i < paramIds.length; i++) {
             if (Object.prototype.hasOwnProperty.call(args, paramIds[i])) {
                 util.pushParam(paramNames[i], args[paramIds[i]]);
+            } else if (paramIds[i].startsWith("SUBSTACK")) {
+                util.pushParam(paramNames[i], {
+                    blockId: util.thread.peekStackFrame().op.id,
+                    fieldId: paramIds[i]
+                });
             } else {
                 util.pushParam(paramNames[i], paramDefaults[i]);
             }
@@ -95,6 +101,7 @@
 
     return (args, util) {
         util.stopThisScript();
+
         // If used outside of a custom block, there may be no stackframe.
         if (util.thread.peekStackFrame()) {
             util.stackFrame.returnValue = args.VALUE;
@@ -132,6 +139,22 @@
         }
         return value;
     }
+
+    argumentStatement (args, util) {
+        const branchInfo = util.getParam(args.VALUE) || {};
+        if (!branchInfo.fieldId) return;
+
+        const blockId = branchInfo.blockId;
+        const block = util.target.blocks.getBlock(blockId);
+        if (!block) return;
+
+        const branch = block.inputs[branchInfo.fieldId];
+        if (!branch) return;
+        const branchId = branch.block;
+
+        // todo: should we wait for the branch to finish?
+        util.thread.pushStack(branchId);
+    }
 }
 
 module.exports = Scratch3ProcedureBlocks;

src/compiler/irgen.js

@@ -796,6 +796,20 @@ class ScriptTreeGenerator {
      */
     descendStackedBlock (block) {
         switch (block.opcode) {
+        case 'argument_statement': {
+            const name = block.fields.VALUE.value;
+            const index = this.script.arguments.lastIndexOf(name);
+            if (index === -1) {
+                return {
+                    kind: 'noop'
+                };
+            }
+            this.script.yields = true;
+            return {
+                kind: 'procedures.statement',
+                name: name
+            };
+        }
         case 'control_all_at_once':
             // In Unsandboxed, attempts to run the script in 1 frame.
             return {
@@ -1477,9 +1491,16 @@ class ScriptTreeGenerator {
             }
         }
 
+        const substacks = {};
         const args = [];
         for (let i = 0; i < paramIds.length; i++) {
             let value;
+
+            if (paramIds[i].startsWith('SUBSTACK')) {
+                substacks[paramNames[i]] = this.descendSubstack(block, paramIds[i]);
+                continue;
+            }
+
             if (block.inputs[paramIds[i]] && block.inputs[paramIds[i]].block) {
                 value = this.descendInputOfBlock(block, paramIds[i]);
             } else {
@@ -1495,7 +1516,8 @@ class ScriptTreeGenerator {
             kind: 'procedures.call',
             code: procedureCode,
             variant,
-            arguments: args
+            arguments: args,
+            substacks
         };
     }
 

src/compiler/jsgen.js

@@ -714,6 +714,7 @@ class JSGenerator {
             const procedureCode = node.code;
             const procedureVariant = node.variant;
             const procedureData = this.ir.procedures[procedureVariant];
+
             if (procedureData.stack === null) {
                 // TODO still need to evaluate arguments for side effects
                 return new TypedInput('""', TYPE_STRING);
@@ -1227,11 +1228,14 @@ class JSGenerator {
             const procedureCode = node.code;
             const procedureVariant = node.variant;
             const procedureData = this.ir.procedures[procedureVariant];
+            this.substacks = node.substacks;
             if (procedureData.stack === null) {
                 // TODO still need to evaluate arguments
                 break;
             }
 
+            this.ir.procedures[procedureVariant].substacks = node.substacks;
+
             const yieldForRecursion = !this.isWarp && procedureCode === this.script.procedureCode;
             if (yieldForRecursion) {
                 this.yieldNotWarp();
@@ -1254,7 +1258,15 @@ class JSGenerator {
         case 'procedures.return':
             this.stopScriptAndReturn(this.descendInput(node.value).asSafe());
             break;
+        case 'procedures.statement': {
+            const procedureVariant = this.script.procedureVariant;
+            const procedureData = this.ir.procedures[procedureVariant];
+            const substacks = procedureData.substacks;
 
+            this.descendStack(substacks[node.name], new Frame(false));
+
+            break;
+        }
         case 'timer.reset':
             this.source += 'runtime.ioDevices.clock.resetProjectTimer();\n';
             break;