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/**
* @license
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Generating Lua for loop blocks.
* @author [email protected] (Rodrigo Queiro)
*/
'use strict';
goog.provide('Blockly.Lua.loops');
goog.require('Blockly.Lua');
/**
* This is the text used to implement a <pre>continue</pre>.
* It is also used to recognise <pre>continue</pre>s in generated code so that
* the appropriate label can be put at the end of the loop body.
* @const {string}
*/
Blockly.Lua.CONTINUE_STATEMENT = 'goto continue\n';
/**
* If the loop body contains a "goto continue" statement, add a continue label
* to the loop body. Slightly inefficient, as continue labels will be generated
* in all outer loops, but this is safer than duplicating the logic of
* blockToCode.
*
* @param {string} branch Generated code of the loop body
* @return {string} Generated label or '' if unnecessary
* @private
*/
Blockly.Lua.addContinueLabel_ = function(branch) {
if (branch.indexOf(Blockly.Lua.CONTINUE_STATEMENT) != -1) {
// False positives are possible (e.g. a string literal), but are harmless.
return branch + Blockly.Lua.INDENT + '::continue::\n';
} else {
return branch;
}
};
Blockly.Lua['controls_repeat_ext'] = function(block) {
// Repeat n times.
if (block.getField('TIMES')) {
// Internal number.
var repeats = String(Number(block.getFieldValue('TIMES')));
} else {
// External number.
var repeats = Blockly.Lua.valueToCode(block, 'TIMES',
Blockly.Lua.ORDER_NONE) || '0';
}
if (Blockly.isNumber(repeats)) {
repeats = parseInt(repeats, 10);
} else {
repeats = 'math.floor(' + repeats + ')';
}
var branch = Blockly.Lua.statementToCode(block, 'DO');
branch = Blockly.Lua.addLoopTrap(branch, block);
branch = Blockly.Lua.addContinueLabel_(branch);
var loopVar = Blockly.Lua.variableDB_.getDistinctName(
'count', Blockly.VARIABLE_CATEGORY_NAME);
var code = 'for ' + loopVar + ' = 1, ' + repeats + ' do\n' +
branch + 'end\n';
return code;
};
Blockly.Lua['controls_repeat'] = Blockly.Lua['controls_repeat_ext'];
Blockly.Lua['controls_whileUntil'] = function(block) {
// Do while/until loop.
var until = block.getFieldValue('MODE') == 'UNTIL';
var argument0 = Blockly.Lua.valueToCode(block, 'BOOL',
until ? Blockly.Lua.ORDER_UNARY :
Blockly.Lua.ORDER_NONE) || 'false';
var branch = Blockly.Lua.statementToCode(block, 'DO');
branch = Blockly.Lua.addLoopTrap(branch, block);
branch = Blockly.Lua.addContinueLabel_(branch);
if (until) {
argument0 = 'not ' + argument0;
}
return 'while ' + argument0 + ' do\n' + branch + 'end\n';
};
Blockly.Lua['controls_for'] = function(block) {
// For loop.
var variable0 = Blockly.Lua.variableDB_.getName(
block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
var startVar = Blockly.Lua.valueToCode(block, 'FROM',
Blockly.Lua.ORDER_NONE) || '0';
var endVar = Blockly.Lua.valueToCode(block, 'TO',
Blockly.Lua.ORDER_NONE) || '0';
var increment = Blockly.Lua.valueToCode(block, 'BY',
Blockly.Lua.ORDER_NONE) || '1';
var branch = Blockly.Lua.statementToCode(block, 'DO');
branch = Blockly.Lua.addLoopTrap(branch, block);
branch = Blockly.Lua.addContinueLabel_(branch);
var code = '';
var incValue;
if (Blockly.isNumber(startVar) && Blockly.isNumber(endVar) &&
Blockly.isNumber(increment)) {
// All arguments are simple numbers.
var up = Number(startVar) <= Number(endVar);
var step = Math.abs(Number(increment));
incValue = (up ? '' : '-') + step;
} else {
code = '';
// Determine loop direction at start, in case one of the bounds
// changes during loop execution.
incValue = Blockly.Lua.variableDB_.getDistinctName(
variable0 + '_inc', Blockly.VARIABLE_CATEGORY_NAME);
code += incValue + ' = ';
if (Blockly.isNumber(increment)) {
code += Math.abs(increment) + '\n';
} else {
code += 'math.abs(' + increment + ')\n';
}
code += 'if (' + startVar + ') > (' + endVar + ') then\n';
code += Blockly.Lua.INDENT + incValue + ' = -' + incValue + '\n';
code += 'end\n';
}
code += 'for ' + variable0 + ' = ' + startVar + ', ' + endVar +
', ' + incValue;
code += ' do\n' + branch + 'end\n';
return code;
};
Blockly.Lua['controls_forEach'] = function(block) {
// For each loop.
var variable0 = Blockly.Lua.variableDB_.getName(
block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
var argument0 = Blockly.Lua.valueToCode(block, 'LIST',
Blockly.Lua.ORDER_NONE) || '{}';
var branch = Blockly.Lua.statementToCode(block, 'DO');
branch = Blockly.Lua.addLoopTrap(branch, block);
branch = Blockly.Lua.addContinueLabel_(branch);
var code = 'for _, ' + variable0 + ' in ipairs(' + argument0 + ') do \n' +
branch + 'end\n';
return code;
};
Blockly.Lua['controls_flow_statements'] = function(block) {
// Flow statements: continue, break.
var xfix = '';
if (Blockly.Lua.STATEMENT_PREFIX) {
// Automatic prefix insertion is switched off for this block. Add manually.
xfix += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_PREFIX, block);
}
if (Blockly.Lua.STATEMENT_SUFFIX) {
// Inject any statement suffix here since the regular one at the end
// will not get executed if the break/continue is triggered.
xfix += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_SUFFIX, block);
}
if (Blockly.Lua.STATEMENT_PREFIX) {
var loop = Blockly.Constants.Loops
.CONTROL_FLOW_IN_LOOP_CHECK_MIXIN.getSurroundLoop(block);
if (loop && !loop.suppressPrefixSuffix) {
// Inject loop's statement prefix here since the regular one at the end
// of the loop will not get executed if 'continue' is triggered.
// In the case of 'break', a prefix is needed due to the loop's suffix.
xfix += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_PREFIX, loop);
}
}
switch (block.getFieldValue('FLOW')) {
case 'BREAK':
return xfix + 'break\n';
case 'CONTINUE':
return xfix + Blockly.Lua.CONTINUE_STATEMENT;
}
throw Error('Unknown flow statement.');
};