122 lines
3.8 KiB
JavaScript
122 lines
3.8 KiB
JavaScript
var Cast = require('../util/cast');
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var Promise = require('promise');
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function Scratch3ControlBlocks(runtime) {
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/**
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* The runtime instantiating this block package.
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* @type {Runtime}
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*/
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this.runtime = runtime;
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}
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/**
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* Retrieve the block primitives implemented by this package.
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* @return {Object.<string, Function>} Mapping of opcode to Function.
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*/
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Scratch3ControlBlocks.prototype.getPrimitives = function() {
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return {
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'control_repeat': this.repeat,
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'control_repeat_until': this.repeatUntil,
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'control_forever': this.forever,
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'control_wait': this.wait,
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'control_if': this.if,
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'control_if_else': this.ifElse,
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'control_stop': this.stop
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};
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};
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Scratch3ControlBlocks.prototype.repeat = function(args, util) {
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var times = Math.floor(Cast.toNumber(args.TIMES));
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// Initialize loop
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if (util.stackFrame.loopCounter === undefined) {
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util.stackFrame.loopCounter = times;
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}
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// Only execute once per frame.
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// When the branch finishes, `repeat` will be executed again and
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// the second branch will be taken, yielding for the rest of the frame.
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if (!util.stackFrame.executedInFrame) {
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util.stackFrame.executedInFrame = true;
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// Decrease counter
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util.stackFrame.loopCounter--;
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// If we still have some left, start the branch.
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if (util.stackFrame.loopCounter >= 0) {
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util.startBranch();
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}
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} else {
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util.stackFrame.executedInFrame = false;
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util.yieldFrame();
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}
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};
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Scratch3ControlBlocks.prototype.repeatUntil = function(args, util) {
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var condition = Cast.toBoolean(args.CONDITION);
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// Only execute once per frame.
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// When the branch finishes, `repeat` will be executed again and
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// the second branch will be taken, yielding for the rest of the frame.
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if (!util.stackFrame.executedInFrame) {
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util.stackFrame.executedInFrame = true;
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// If the condition is true, start the branch.
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if (!condition) {
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util.startBranch();
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}
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} else {
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util.stackFrame.executedInFrame = false;
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util.yieldFrame();
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}
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};
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Scratch3ControlBlocks.prototype.forever = function(args, util) {
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// Only execute once per frame.
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// When the branch finishes, `forever` will be executed again and
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// the second branch will be taken, yielding for the rest of the frame.
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if (!util.stackFrame.executedInFrame) {
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util.stackFrame.executedInFrame = true;
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util.startBranch();
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} else {
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util.stackFrame.executedInFrame = false;
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util.yieldFrame();
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}
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};
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Scratch3ControlBlocks.prototype.wait = function(args) {
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var duration = Cast.toNumber(args.DURATION);
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return new Promise(function(resolve) {
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setTimeout(function() {
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resolve();
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}, 1000 * duration);
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});
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};
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Scratch3ControlBlocks.prototype.if = function(args, util) {
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var condition = Cast.toBoolean(args.CONDITION);
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// Only execute one time. `if` will be returned to
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// when the branch finishes, but it shouldn't execute again.
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if (util.stackFrame.executedInFrame === undefined) {
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util.stackFrame.executedInFrame = true;
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if (condition) {
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util.startBranch();
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}
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}
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};
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Scratch3ControlBlocks.prototype.ifElse = function(args, util) {
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var condition = Cast.toBoolean(args.CONDITION);
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// Only execute one time. `ifElse` will be returned to
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// when the branch finishes, but it shouldn't execute again.
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if (util.stackFrame.executedInFrame === undefined) {
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util.stackFrame.executedInFrame = true;
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if (condition) {
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util.startBranch(1);
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} else {
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util.startBranch(2);
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}
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}
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};
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Scratch3ControlBlocks.prototype.stop = function() {
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// @todo - don't use this.runtime
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this.runtime.stopAll();
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};
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module.exports = Scratch3ControlBlocks;
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