generators/python/loops.js
/**
* @license
* Visual Blocks Language
*
* Copyright 2012 Google Inc.
* https://blockly.googlecode.com/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @fileoverview Generating Python for loop blocks.
* @author q.neutron@gmail.com (Quynh Neutron)
*/
'use strict';
goog.provide('Blockly.Python.loops');
goog.require('Blockly.Python');
Blockly.Python.LOOP_PASS = ' pass\n';
Blockly.Python['controls_repeat'] = function(block) {
// Repeat n times (internal number).
var repeats = parseInt(block.getFieldValue('TIMES'), 10);
var branch = Blockly.Python.statementToCode(block, 'DO');
branch = Blockly.Python.addLoopTrap(branch, block.id) ||
Blockly.Python.LOOP_PASS;
var loopVar = Blockly.Python.variableDB_.getDistinctName(
'count', Blockly.Variables.NAME_TYPE);
var code = 'for ' + loopVar + ' in range(' + repeats + '):\n' + branch;
return code;
};
Blockly.Python['controls_repeat_ext'] = function(block) {
// Repeat n times (external number).
var repeats = Blockly.Python.valueToCode(block, 'TIMES',
Blockly.Python.ORDER_NONE) || '0';
if (Blockly.isNumber(repeats)) {
repeats = parseInt(repeats, 10);
} else {
repeats = 'int(' + repeats + ')';
}
var branch = Blockly.Python.statementToCode(block, 'DO');
branch = Blockly.Python.addLoopTrap(branch, block.id) ||
Blockly.Python.LOOP_PASS;
var loopVar = Blockly.Python.variableDB_.getDistinctName(
'count', Blockly.Variables.NAME_TYPE);
var code = 'for ' + loopVar + ' in range(' + repeats + '):\n' + branch;
return code;
};
Blockly.Python['controls_whileUntil'] = function(block) {
// Do while/until loop.
var until = block.getFieldValue('MODE') == 'UNTIL';
var argument0 = Blockly.Python.valueToCode(block, 'BOOL',
until ? Blockly.Python.ORDER_LOGICAL_NOT :
Blockly.Python.ORDER_NONE) || 'False';
var branch = Blockly.Python.statementToCode(block, 'DO');
branch = Blockly.Python.addLoopTrap(branch, block.id) ||
Blockly.Python.LOOP_PASS;
if (until) {
argument0 = 'not ' + argument0;
}
return 'while ' + argument0 + ':\n' + branch;
};
Blockly.Python['controls_for'] = function(block) {
// For loop.
var variable0 = Blockly.Python.variableDB_.getName(
block.getFieldValue('VAR'), Blockly.Variables.NAME_TYPE);
var argument0 = Blockly.Python.valueToCode(block, 'FROM',
Blockly.Python.ORDER_NONE) || '0';
var argument1 = Blockly.Python.valueToCode(block, 'TO',
Blockly.Python.ORDER_NONE) || '0';
var increment = Blockly.Python.valueToCode(block, 'BY',
Blockly.Python.ORDER_NONE) || '1';
var branch = Blockly.Python.statementToCode(block, 'DO');
branch = Blockly.Python.addLoopTrap(branch, block.id) ||
Blockly.Python.LOOP_PASS;
var code = '';
var range;
// Helper functions.
var defineUpRange = function() {
return Blockly.Python.provideFunction_(
'upRange',
['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ +
'(start, stop, step):',
' while start <= stop:',
' yield start',
' start += abs(step)']);
};
var defineDownRange = function() {
return Blockly.Python.provideFunction_(
'downRange',
['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ +
'(start, stop, step):',
' while start >= stop:',
' yield start',
' start -= abs(step)']);
};
// Arguments are legal Python code (numbers or strings returned by scrub()).
var generateUpDownRange = function(start, end, inc) {
return '(' + start + ' <= ' + end + ') and ' +
defineUpRange() + '(' + start + ', ' + end + ', ' + inc + ') or ' +
defineDownRange() + '(' + start + ', ' + end + ', ' + inc + ')';
};
if (Blockly.isNumber(argument0) && Blockly.isNumber(argument1) &&
Blockly.isNumber(increment)) {
// All parameters are simple numbers.
argument0 = parseFloat(argument0);
argument1 = parseFloat(argument1);
increment = Math.abs(parseFloat(increment));
if (argument0 % 1 === 0 && argument1 % 1 === 0 && increment % 1 === 0) {
// All parameters are integers.
if (argument0 <= argument1) {
// Count up.
argument1++;
if (argument0 == 0 && increment == 1) {
// If starting index is 0, omit it.
range = argument1;
} else {
range = argument0 + ', ' + argument1;
}
// If increment isn't 1, it must be explicit.
if (increment != 1) {
range += ', ' + increment;
}
} else {
// Count down.
argument1--;
range = argument0 + ', ' + argument1 + ', -' + increment;
}
range = 'range(' + range + ')';
} else {
// At least one of the parameters is not an integer.
if (argument0 < argument1) {
range = defineUpRange();
} else {
range = defineDownRange();
}
range += '(' + argument0 + ', ' + argument1 + ', ' + increment + ')';
}
} else {
// Cache non-trivial values to variables to prevent repeated look-ups.
var scrub = function(arg, suffix) {
if (Blockly.isNumber(arg)) {
// Simple number.
arg = parseFloat(arg);
} else if (arg.match(/^\w+$/)) {
// Variable.
arg = 'float(' + arg + ')';
} else {
// It's complicated.
var varName = Blockly.Python.variableDB_.getDistinctName(
variable0 + suffix, Blockly.Variables.NAME_TYPE);
code += varName + ' = float(' + arg + ')\n';
arg = varName;
}
return arg;
};
var startVar = scrub(argument0, '_start');
var endVar = scrub(argument1, '_end');
var incVar = scrub(increment, '_inc');
if (typeof startVar == 'number' && typeof endVar == 'number') {
if (startVar < endVar) {
range = defineUpRange(startVar, endVar, increment);
} else {
range = defineDownRange(startVar, endVar, increment);
}
} else {
// We cannot determine direction statically.
range = generateUpDownRange(startVar, endVar, increment);
}
}
code += 'for ' + variable0 + ' in ' + range + ':\n' + branch;
return code;
};
Blockly.Python['controls_forEach'] = function(block) {
// For each loop.
var variable0 = Blockly.Python.variableDB_.getName(
block.getFieldValue('VAR'), Blockly.Variables.NAME_TYPE);
var argument0 = Blockly.Python.valueToCode(block, 'LIST',
Blockly.Python.ORDER_RELATIONAL) || '[]';
var branch = Blockly.Python.statementToCode(block, 'DO');
branch = Blockly.Python.addLoopTrap(branch, block.id) ||
Blockly.Python.LOOP_PASS;
var code = 'for ' + variable0 + ' in ' + argument0 + ':\n' + branch;
return code;
};
Blockly.Python['controls_flow_statements'] = function(block) {
// Flow statements: continue, break.
switch (block.getFieldValue('FLOW')) {
case 'BREAK':
return 'break\n';
case 'CONTINUE':
return 'continue\n';
}
throw 'Unknown flow statement.';
};