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Compatibility implementation

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Florrie 2018-03-22 18:55:36 -03:00
parent 00b151b9ff
commit 1db4a2c7a7
1 changed files with 6 additions and 84 deletions
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90
src/blocks/scratch3_control.js
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@ -66,92 +66,14 @@ class Scratch3ControlBlocks {
const variable = util.target.lookupOrCreateVariable( const variable = util.target.lookupOrCreateVariable(
args.VARIABLE.id, args.VARIABLE.name); args.VARIABLE.id, args.VARIABLE.name);
// The for-each block has two different but similar modes of operation, if (typeof util.stackFrame.index === 'undefined') {
// based on the value to be iterated: util.stackFrame.index = 0;
//
// 1. If the value is a string, keep INTERNAL track of the index.
// The value assigned to the Scratch variable will be the letter at
// the current index, which will increase by 1 each tick. For example:
//
// for each (x) in [abcdef]:
// say (x)
//
// ..is equivalent to:
//
// set (i_) to 0
// repeat until (i_) > length of [abcdef]:
// change (i_) by 1
// set (x) to letter (i_) of [abcdef]
// say (x)
//
// In this example, i_ is effectively invisible to the Scratch code:
// There is no way to view or change it. Also, changing (x) has no
// effect on the next iteration.
//
// 2. If the value is a number, DO NOT keep internal track of the index.
// When for-each is passed a number, it iterates over all the numbers
// from 1 to that number (inclusive). For example:
//
// for each (x) in [10]:
// say (x)
//
// ..is equivalent to:
//
// set (x) to 0
// repeat until (x) > 10:
// change (x) by 1
// say (x)
//
// The critical difference is that (x) is just a normal Scratch
// variable. Changing it DOES have an effect on the next iteration.
// This makes it possible to "skip" items, or to go back, et cetera.
// For example:
//
// for each (x) in [10]:
// if (x) mod 4 = 0:
// say [Mod 4 - Skip the next.]
// change (x) by 1
// else:
// say x
//
// ..would say 1, 2, 3, "Mod 4", 6, 7, "Mod 4", 10.
//
// The mode of operation above is decided at the beginning of the for-
// each loop, and changing the value that is being iterated *while* it
// is being iterated does not change the mode.
if (typeof util.stackFrame.iterationMode === 'undefined') {
const value = args.VALUE;
let mode;
if (typeof value === 'string' && !isNaN(Number(value))) {
mode = 'number';
} else if (typeof value === 'number') {
mode = 'number';
} else {
mode = 'string';
}
if (mode === 'number') {
variable.value = 0;
} else {
util.stackFrame.stringIndex = 0;
}
util.stackFrame.iterationMode = mode;
} }
if (util.stackFrame.iterationMode === 'string') { if (util.stackFrame.index < Number(args.VALUE)) {
if (util.stackFrame.stringIndex < args.VALUE.length) { util.stackFrame.index++;
variable.value = args.VALUE[util.stackFrame.stringIndex++]; variable.value = util.stackFrame.index;
util.startBranch(1, true); util.startBranch(1, true);
}
}
if (util.stackFrame.iterationMode === 'number') {
if (variable.value < Number(args.VALUE)) {
variable.value++;
util.startBranch(1, true);
}
} }
} }