refactor(generators): Restructure generator modules to contain side effects (#7173)

* refactor(generators): Move lang.js -> lang/lang_gernator.js Move the LangGenerator definitions into their respective subdirectories and add a _generator suffix to their filenames, i.e. generators/javascript.js becomes generators/javascript/javascript_generator.js. This is to keep related code together and allow the `lang/all.js` entrypoints to be moved to the top level generators/ directory. No goog module IDs were changed, so playground and test code that accesses this modules by filename does not need to be modified. * refactor(generators) Move lang/all.js -> lang.js - Move the entrypoints in generators/*/all.js to correspondingly-named files in generators/ instead—i.e., generators/javascript/all.js becomes generators/javascript.js. - Update build_tasks.js accordingly. * fix(generators): Add missing exports for LuaGenerator, PhpGenerator These were inadvertently omitted from #7161 and #7162, respectively. * refactor(generators): Make block generator modules side-effect free - Move declaration of <lang>Generator instance from generators/<lang>/<lang>_generator.js to generators/<lang>.js. - Move .addReservedWords() calls from generators/<lang>/*.js to generators/<lang>.js - Modify generators/<lang>/*.js to export block generator functions individually, rather than installing on <lang>Generator instance. - Modify generators/<lang>.js to import and install block generator functions on <lang>Generator instance. * fix(tests): Fix tests broken by restructuring of generators Where these tests needed block generator functions preinstalled they should have been importing the Blockly.<Lang>.all module. Where they do not need the provided block generator functions they can now create their own empty <Lang>Generator instances. * chore: Update renamings file - Fix a malformation in previous entries that was not detected by the renaming file validator test. - Add entries describing the work done in this and related recent PRs. * fix: Correct minor errors in PR #7173 - Fix a search-and-replace error in renamings.json5 - Fix an incorrect-but-usable import in generator_test.js
2026-01-10 10:27:08 +01:00 · 2023-06-20 23:22:44 +01:00
parent 021a560ef0
commit 130989763c
64 changed files with 2120 additions and 2046 deletions
--- a/generators/python/all.js
+++ b/generators/python/all.js
@@ -1,26 +0,0 @@
-/**
- * @license
- * Copyright 2021 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-/**
- * @fileoverview Complete helper functions for generating Python for
- *     blocks.  This is the entrypoint for python_compressed.js.
- * @suppress {extraRequire}
- */
-
-import * as goog from '../../closure/goog/goog.js';
-goog.declareModuleId('Blockly.Python.all');
-
-import './colour.js';
-import './lists.js';
-import './logic.js';
-import './loops.js';
-import './math.js';
-import './procedures.js';
-import './text.js';
-import './variables.js';
-import './variables_dynamic.js';
-
-export * from '../python.js';
--- a/generators/python/colour.js
+++ b/generators/python/colour.js
@@ -11,23 +11,23 @@
 import * as goog from '../../closure/goog/goog.js';
 goog.declareModuleId('Blockly.Python.colour');

-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['colour_picker'] = function(block, generator) {
+export function colour_picker(block, generator) {
  // Colour picker.
  const code = generator.quote_(block.getFieldValue('COLOUR'));
  return [code, Order.ATOMIC];
 };

-pythonGenerator.forBlock['colour_random'] = function(block, generator) {
+export function colour_random(block, generator) {
  // Generate a random colour.
  generator.definitions_['import_random'] = 'import random';
  const code = '\'#%06x\' % random.randint(0, 2**24 - 1)';
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['colour_rgb'] = function(block, generator) {
+export function colour_rgb(block, generator) {
  // Compose a colour from RGB components expressed as percentages.
  const functionName = generator.provideFunction_('colour_rgb', `
 def ${generator.FUNCTION_NAME_PLACEHOLDER_}(r, g, b):
@@ -43,7 +43,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(r, g, b):
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['colour_blend'] = function(block, generator) {
+export function colour_blend(block, generator) {
  // Blend two colours together.
  const functionName = generator.provideFunction_('colour_blend', `
 def ${generator.FUNCTION_NAME_PLACEHOLDER_}(colour1, colour2, ratio):
--- a/generators/python/lists.js
+++ b/generators/python/lists.js
@@ -13,15 +13,15 @@ goog.declareModuleId('Blockly.Python.lists');

 import * as stringUtils from '../../core/utils/string.js';
 import {NameType} from '../../core/names.js';
-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['lists_create_empty'] = function(block, generator) {
+export function lists_create_empty(block, generator) {
  // Create an empty list.
  return ['[]', Order.ATOMIC];
 };

-pythonGenerator.forBlock['lists_create_with'] = function(block, generator) {
+export function lists_create_with(block, generator) {
  // Create a list with any number of elements of any type.
  const elements = new Array(block.itemCount_);
  for (let i = 0; i < block.itemCount_; i++) {
@@ -32,7 +32,7 @@ pythonGenerator.forBlock['lists_create_with'] = function(block, generator) {
  return [code, Order.ATOMIC];
 };

-pythonGenerator.forBlock['lists_repeat'] = function(block, generator) {
+export function lists_repeat(block, generator) {
  // Create a list with one element repeated.
  const item = generator.valueToCode(block, 'ITEM', Order.NONE) || 'None';
  const times =
@@ -41,20 +41,20 @@ pythonGenerator.forBlock['lists_repeat'] = function(block, generator) {
  return [code, Order.MULTIPLICATIVE];
 };

-pythonGenerator.forBlock['lists_length'] = function(block, generator) {
+export function lists_length(block, generator) {
  // String or array length.
  const list = generator.valueToCode(block, 'VALUE', Order.NONE) || '[]';
  return ['len(' + list + ')', Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['lists_isEmpty'] = function(block, generator) {
+export function lists_isEmpty(block, generator) {
  // Is the string null or array empty?
  const list = generator.valueToCode(block, 'VALUE', Order.NONE) || '[]';
  const code = 'not len(' + list + ')';
  return [code, Order.LOGICAL_NOT];
 };

-pythonGenerator.forBlock['lists_indexOf'] = function(block, generator) {
+export function lists_indexOf(block, generator) {
  // Find an item in the list.
  const item = generator.valueToCode(block, 'FIND', Order.NONE) || '[]';
  const list = generator.valueToCode(block, 'VALUE', Order.NONE) || "''";
@@ -88,7 +88,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(my_list, elem):
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['lists_getIndex'] = function(block, generator) {
+export function lists_getIndex(block, generator) {
  // Get element at index.
  // Note: Until January 2013 this block did not have MODE or WHERE inputs.
  const mode = block.getFieldValue('MODE') || 'GET';
@@ -170,7 +170,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(myList):
  throw Error('Unhandled combination (lists_getIndex).');
 };

-pythonGenerator.forBlock['lists_setIndex'] = function(block, generator) {
+export function lists_setIndex(block, generator) {
  // Set element at index.
  // Note: Until February 2013 this block did not have MODE or WHERE inputs.
  let list = generator.valueToCode(block, 'LIST', Order.MEMBER) || '[]';
@@ -242,7 +242,7 @@ pythonGenerator.forBlock['lists_setIndex'] = function(block, generator) {
  throw Error('Unhandled combination (lists_setIndex).');
 };

-pythonGenerator.forBlock['lists_getSublist'] = function(block, generator) {
+export function lists_getSublist(block, generator) {
  // Get sublist.
  const list = generator.valueToCode(block, 'LIST', Order.MEMBER) || '[]';
  const where1 = block.getFieldValue('WHERE1');
@@ -291,7 +291,7 @@ pythonGenerator.forBlock['lists_getSublist'] = function(block, generator) {
  return [code, Order.MEMBER];
 };

-pythonGenerator.forBlock['lists_sort'] = function(block, generator) {
+export function lists_sort(block, generator) {
  // Block for sorting a list.
  const list = (generator.valueToCode(block, 'LIST', Order.NONE) || '[]');
  const type = block.getFieldValue('TYPE');
@@ -318,7 +318,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(my_list, type, reverse):
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['lists_split'] = function(block, generator) {
+export function lists_split(block, generator) {
  // Block for splitting text into a list, or joining a list into text.
  const mode = block.getFieldValue('MODE');
  let code;
@@ -339,7 +339,7 @@ pythonGenerator.forBlock['lists_split'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['lists_reverse'] = function(block, generator) {
+export function lists_reverse(block, generator) {
  // Block for reversing a list.
  const list = generator.valueToCode(block, 'LIST', Order.NONE) || '[]';
  const code = 'list(reversed(' + list + '))';
--- a/generators/python/logic.js
+++ b/generators/python/logic.js
@@ -11,10 +11,10 @@
 import * as goog from '../../closure/goog/goog.js';
 goog.declareModuleId('Blockly.Python.logic');

-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['controls_if'] = function(block, generator) {
+export function controls_if(block, generator) {
  // If/elseif/else condition.
  let n = 0;
  let code = '', branchCode, conditionCode;
@@ -55,10 +55,9 @@ pythonGenerator.forBlock['controls_if'] = function(block, generator) {
  return code;
 };

-pythonGenerator.forBlock['controls_ifelse'] =
-    pythonGenerator.forBlock['controls_if'];
+export const controls_ifelse = controls_if;

-pythonGenerator.forBlock['logic_compare'] = function(block, generator) {
+export function logic_compare(block, generator) {
  // Comparison operator.
  const OPERATORS =
      {'EQ': '==', 'NEQ': '!=', 'LT': '<', 'LTE': '<=', 'GT': '>', 'GTE': '>='};
@@ -70,7 +69,7 @@ pythonGenerator.forBlock['logic_compare'] = function(block, generator) {
  return [code, order];
 };

-pythonGenerator.forBlock['logic_operation'] = function(block, generator) {
+export function logic_operation(block, generator) {
  // Operations 'and', 'or'.
  const operator = (block.getFieldValue('OP') === 'AND') ? 'and' : 'or';
  const order =
@@ -95,7 +94,7 @@ pythonGenerator.forBlock['logic_operation'] = function(block, generator) {
  return [code, order];
 };

-pythonGenerator.forBlock['logic_negate'] = function(block, generator) {
+export function logic_negate(block, generator) {
  // Negation.
  const argument0 =
      generator.valueToCode(block, 'BOOL', Order.LOGICAL_NOT) || 'True';
@@ -103,18 +102,18 @@ pythonGenerator.forBlock['logic_negate'] = function(block, generator) {
  return [code, Order.LOGICAL_NOT];
 };

-pythonGenerator.forBlock['logic_boolean'] = function(block, generator) {
+export function logic_boolean(block, generator) {
  // Boolean values true and false.
  const code = (block.getFieldValue('BOOL') === 'TRUE') ? 'True' : 'False';
  return [code, Order.ATOMIC];
 };

-pythonGenerator.forBlock['logic_null'] = function(block, generator) {
+export function logic_null(block, generator) {
  // Null data type.
  return ['None', Order.ATOMIC];
 };

-pythonGenerator.forBlock['logic_ternary'] = function(block, generator) {
+export function logic_ternary(block, generator) {
  // Ternary operator.
  const value_if =
      generator.valueToCode(block, 'IF', Order.CONDITIONAL) || 'False';
--- a/generators/python/loops.js
+++ b/generators/python/loops.js
@@ -13,10 +13,10 @@ goog.declareModuleId('Blockly.Python.loops');

 import * as stringUtils from '../../core/utils/string.js';
 import {NameType} from '../../core/names.js';
-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['controls_repeat_ext'] = function(block, generator) {
+export function controls_repeat_ext(block, generator) {
  // Repeat n times.
  let repeats;
  if (block.getField('TIMES')) {
@@ -39,10 +39,9 @@ pythonGenerator.forBlock['controls_repeat_ext'] = function(block, generator) {
  return code;
 };

-pythonGenerator.forBlock['controls_repeat'] =
-    pythonGenerator.forBlock['controls_repeat_ext'];
+export const controls_repeat = controls_repeat_ext;

-pythonGenerator.forBlock['controls_whileUntil'] = function(block, generator) {
+export function controls_whileUntil(block, generator) {
  // Do while/until loop.
  const until = block.getFieldValue('MODE') === 'UNTIL';
  let argument0 = generator.valueToCode(
@@ -57,7 +56,7 @@ pythonGenerator.forBlock['controls_whileUntil'] = function(block, generator) {
  return 'while ' + argument0 + ':\n' + branch;
 };

-pythonGenerator.forBlock['controls_for'] = function(block, generator) {
+export function controls_for(block, generator) {
  // For loop.
  const variable0 =
      generator.nameDB_.getName(
@@ -166,7 +165,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(start, stop, step):
  return code;
 };

-pythonGenerator.forBlock['controls_forEach'] = function(block, generator) {
+export function controls_forEach(block, generator) {
  // For each loop.
  const variable0 =
      generator.nameDB_.getName(
@@ -179,7 +178,7 @@ pythonGenerator.forBlock['controls_forEach'] = function(block, generator) {
  return code;
 };

-pythonGenerator.forBlock['controls_flow_statements'] = function(block, generator) {
+export function controls_flow_statements(block, generator) {
  // Flow statements: continue, break.
  let xfix = '';
  if (generator.STATEMENT_PREFIX) {
--- a/generators/python/math.js
+++ b/generators/python/math.js
@@ -12,13 +12,13 @@ import * as goog from '../../closure/goog/goog.js';
 goog.declareModuleId('Blockly.Python.math');

 import {NameType} from '../../core/names.js';
-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


 // If any new block imports any library, add that library name here.
-pythonGenerator.addReservedWords('math,random,Number');
+// RESERVED WORDS: 'math,random,Number'

-pythonGenerator.forBlock['math_number'] = function(block, generator) {
+export function math_number(block, generator) {
  // Numeric value.
  let code = Number(block.getFieldValue('NUM'));
  let order;
@@ -34,7 +34,7 @@ pythonGenerator.forBlock['math_number'] = function(block, generator) {
  return [code, order];
 };

-pythonGenerator.forBlock['math_arithmetic'] = function(block, generator) {
+export function math_arithmetic(block, generator) {
  // Basic arithmetic operators, and power.
  const OPERATORS = {
    'ADD': [' + ', Order.ADDITIVE],
@@ -57,7 +57,7 @@ pythonGenerator.forBlock['math_arithmetic'] = function(block, generator) {
  // legibility of the generated code.
 };

-pythonGenerator.forBlock['math_single'] = function(block, generator) {
+export function math_single(block, generator) {
  // Math operators with single operand.
  const operator = block.getFieldValue('OP');
  let code;
@@ -135,7 +135,7 @@ pythonGenerator.forBlock['math_single'] = function(block, generator) {
  return [code, Order.MULTIPLICATIVE];
 };

-pythonGenerator.forBlock['math_constant'] = function(block, generator) {
+export function math_constant(block, generator) {
  // Constants: PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2), INFINITY.
  const CONSTANTS = {
    'PI': ['math.pi', Order.MEMBER],
@@ -152,7 +152,7 @@ pythonGenerator.forBlock['math_constant'] = function(block, generator) {
  return CONSTANTS[constant];
 };

-pythonGenerator.forBlock['math_number_property'] = function(block, generator) {
+export function math_number_property(block, generator) {
   // Check if a number is even, odd, prime, whole, positive, or negative
   // or if it is divisible by certain number. Returns true or false.
  const PROPERTIES = {
@@ -211,7 +211,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(n):
  return [code, outputOrder];
 };

-pythonGenerator.forBlock['math_change'] = function(block, generator) {
+export function math_change(block, generator) {
  // Add to a variable in place.
  generator.definitions_['from_numbers_import_Number'] =
      'from numbers import Number';
@@ -225,13 +225,11 @@ pythonGenerator.forBlock['math_change'] = function(block, generator) {
 };

 // Rounding functions have a single operand.
-pythonGenerator.forBlock['math_round'] =
-    pythonGenerator.forBlock['math_single'];
+export const math_round = math_single;
 // Trigonometry functions have a single operand.
-pythonGenerator.forBlock['math_trig'] =
-    pythonGenerator.forBlock['math_single'];
+export const math_trig = math_single;

-pythonGenerator.forBlock['math_on_list'] = function(block, generator) {
+export function math_on_list(block, generator) {
  // Math functions for lists.
  const func = block.getFieldValue('OP');
  const list = generator.valueToCode(block, 'LIST', Order.NONE) || '[]';
@@ -329,7 +327,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(numbers):
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['math_modulo'] = function(block, generator) {
+export function math_modulo(block, generator) {
  // Remainder computation.
  const argument0 =
      generator.valueToCode(block, 'DIVIDEND', Order.MULTIPLICATIVE) ||
@@ -341,7 +339,7 @@ pythonGenerator.forBlock['math_modulo'] = function(block, generator) {
  return [code, Order.MULTIPLICATIVE];
 };

-pythonGenerator.forBlock['math_constrain'] = function(block, generator) {
+export function math_constrain(block, generator) {
  // Constrain a number between two limits.
  const argument0 =
      generator.valueToCode(block, 'VALUE', Order.NONE) || '0';
@@ -355,7 +353,7 @@ pythonGenerator.forBlock['math_constrain'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['math_random_int'] = function(block, generator) {
+export function math_random_int(block, generator) {
  // Random integer between [X] and [Y].
  generator.definitions_['import_random'] = 'import random';
  const argument0 =
@@ -366,13 +364,13 @@ pythonGenerator.forBlock['math_random_int'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['math_random_float'] = function(block, generator) {
+export function math_random_float(block, generator) {
  // Random fraction between 0 and 1.
  generator.definitions_['import_random'] = 'import random';
  return ['random.random()', Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['math_atan2'] = function(block, generator) {
+export function math_atan2(block, generator) {
  // Arctangent of point (X, Y) in degrees from -180 to 180.
  generator.definitions_['import_math'] = 'import math';
  const argument0 = generator.valueToCode(block, 'X', Order.NONE) || '0';
--- a/generators/python/procedures.js
+++ b/generators/python/procedures.js
@@ -13,10 +13,10 @@ goog.declareModuleId('Blockly.Python.procedures');

 import * as Variables from '../../core/variables.js';
 import {NameType} from '../../core/names.js';
-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['procedures_defreturn'] = function(block, generator) {
+export function procedures_defreturn(block, generator) {
  // Define a procedure with a return value.
  // First, add a 'global' statement for every variable that is not shadowed by
  // a local parameter.
@@ -87,10 +87,9 @@ pythonGenerator.forBlock['procedures_defreturn'] = function(block, generator) {

 // Defining a procedure without a return value uses the same generator as
 // a procedure with a return value.
-pythonGenerator.forBlock['procedures_defnoreturn'] =
-    pythonGenerator.forBlock['procedures_defreturn'];
+export const procedures_defnoreturn = procedures_defreturn;

-pythonGenerator.forBlock['procedures_callreturn'] = function(block, generator) {
+export function procedures_callreturn(block, generator) {
  // Call a procedure with a return value.
  const funcName =
      generator.nameDB_.getName(
@@ -105,7 +104,7 @@ pythonGenerator.forBlock['procedures_callreturn'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['procedures_callnoreturn'] = function(block, generator) {
+export function procedures_callnoreturn(block, generator) {
  // Call a procedure with no return value.
  // Generated code is for a function call as a statement is the same as a
  // function call as a value, with the addition of line ending.
@@ -113,7 +112,7 @@ pythonGenerator.forBlock['procedures_callnoreturn'] = function(block, generator)
  return tuple[0] + '\n';
 };

-pythonGenerator.forBlock['procedures_ifreturn'] = function(block, generator) {
+export function procedures_ifreturn(block, generator) {
  // Conditionally return value from a procedure.
  const condition =
      generator.valueToCode(block, 'CONDITION', Order.NONE) || 'False';
--- a/generators/python/python_generator.js
+++ b/generators/python/python_generator.js
@@ -0,0 +1,340 @@
+/**
+ * @license
+ * Copyright 2012 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Helper functions for generating Python for blocks.
+ * @suppress {checkTypes|globalThis}
+ */
+
+import * as goog from '../../closure/goog/goog.js';
+goog.declareModuleId('Blockly.Python');
+
+import * as stringUtils from '../../core/utils/string.js';
+import * as Variables from '../../core/variables.js';
+// import type {Block} from '../../core/block.js';
+import {CodeGenerator} from '../../core/generator.js';
+import {Names, NameType} from '../../core/names.js';
+// import type {Workspace} from '../../core/workspace.js';
+import {inputTypes} from '../../core/inputs/input_types.js';
+
+
+/**
+ * Order of operation ENUMs.
+ * http://docs.python.org/reference/expressions.html#summary
+ * @enum {number}
+ */
+export const Order = {
+  ATOMIC: 0,             // 0 "" ...
+  COLLECTION: 1,         // tuples, lists, dictionaries
+  STRING_CONVERSION: 1,  // `expression...`
+  MEMBER: 2.1,           // . []
+  FUNCTION_CALL: 2.2,    // ()
+  EXPONENTIATION: 3,     // **
+  UNARY_SIGN: 4,         // + -
+  BITWISE_NOT: 4,        // ~
+  MULTIPLICATIVE: 5,     // * / // %
+  ADDITIVE: 6,           // + -
+  BITWISE_SHIFT: 7,      // << >>
+  BITWISE_AND: 8,        // &
+  BITWISE_XOR: 9,        // ^
+  BITWISE_OR: 10,        // |
+  RELATIONAL: 11,        // in, not in, is, is not, >, >=, <>, !=, ==
+  LOGICAL_NOT: 12,       // not
+  LOGICAL_AND: 13,       // and
+  LOGICAL_OR: 14,        // or
+  CONDITIONAL: 15,       // if else
+  LAMBDA: 16,            // lambda
+  NONE: 99,              // (...)
+};
+
+/**
+ * PythonScript code generator class.
+ */
+export class PythonGenerator extends CodeGenerator {
+  /**
+   * List of outer-inner pairings that do NOT require parentheses.
+   * @type {!Array<!Array<number>>}
+   */
+  ORDER_OVERRIDES = [
+    // (foo()).bar -> foo().bar
+    // (foo())[0] -> foo()[0]
+    [Order.FUNCTION_CALL, Order.MEMBER],
+    // (foo())() -> foo()()
+    [Order.FUNCTION_CALL, Order.FUNCTION_CALL],
+    // (foo.bar).baz -> foo.bar.baz
+    // (foo.bar)[0] -> foo.bar[0]
+    // (foo[0]).bar -> foo[0].bar
+    // (foo[0])[1] -> foo[0][1]
+    [Order.MEMBER, Order.MEMBER],
+    // (foo.bar)() -> foo.bar()
+    // (foo[0])() -> foo[0]()
+    [Order.MEMBER, Order.FUNCTION_CALL],
+  
+    // not (not foo) -> not not foo
+    [Order.LOGICAL_NOT, Order.LOGICAL_NOT],
+    // a and (b and c) -> a and b and c
+    [Order.LOGICAL_AND, Order.LOGICAL_AND],
+    // a or (b or c) -> a or b or c
+    [Order.LOGICAL_OR, Order.LOGICAL_OR]
+  ];
+  
+  constructor(name) {
+    super(name ?? 'Python');
+    this.isInitialized = false;
+
+    // Copy Order values onto instance for backwards compatibility
+    // while ensuring they are not part of the publically-advertised
+    // API.
+    //
+    // TODO(#7085): deprecate these in due course.  (Could initially
+    // replace data properties with get accessors that call
+    // deprecate.warn().)
+    for (const key in Order) {
+      this['ORDER_' + key] = Order[key];
+    }
+
+    // List of illegal variable names.  This is not intended to be a
+    // security feature.  Blockly is 100% client-side, so bypassing
+    // this list is trivial.  This is intended to prevent users from
+    // accidentally clobbering a built-in object or function.
+    this.addReservedWords(
+      // import keyword
+      // print(','.join(sorted(keyword.kwlist)))
+      // https://docs.python.org/3/reference/lexical_analysis.html#keywords
+      // https://docs.python.org/2/reference/lexical_analysis.html#keywords
+      'False,None,True,and,as,assert,break,class,continue,def,del,elif,else,' +
+      'except,exec,finally,for,from,global,if,import,in,is,lambda,nonlocal,' +
+      'not,or,pass,print,raise,return,try,while,with,yield,' +
+      // https://docs.python.org/3/library/constants.html
+      // https://docs.python.org/2/library/constants.html
+      'NotImplemented,Ellipsis,__debug__,quit,exit,copyright,license,credits,' +
+      // >>> print(','.join(sorted(dir(__builtins__))))
+      // https://docs.python.org/3/library/functions.html
+      // https://docs.python.org/2/library/functions.html
+      'ArithmeticError,AssertionError,AttributeError,BaseException,' +
+      'BlockingIOError,BrokenPipeError,BufferError,BytesWarning,' +
+      'ChildProcessError,ConnectionAbortedError,ConnectionError,' +
+      'ConnectionRefusedError,ConnectionResetError,DeprecationWarning,' +
+      'EOFError,Ellipsis,EnvironmentError,Exception,FileExistsError,' +
+      'FileNotFoundError,FloatingPointError,FutureWarning,GeneratorExit,' +
+      'IOError,ImportError,ImportWarning,IndentationError,IndexError,' +
+      'InterruptedError,IsADirectoryError,KeyError,KeyboardInterrupt,' +
+      'LookupError,MemoryError,ModuleNotFoundError,NameError,' +
+      'NotADirectoryError,NotImplemented,NotImplementedError,OSError,' +
+      'OverflowError,PendingDeprecationWarning,PermissionError,' +
+      'ProcessLookupError,RecursionError,ReferenceError,ResourceWarning,' +
+      'RuntimeError,RuntimeWarning,StandardError,StopAsyncIteration,' +
+      'StopIteration,SyntaxError,SyntaxWarning,SystemError,SystemExit,' +
+      'TabError,TimeoutError,TypeError,UnboundLocalError,UnicodeDecodeError,' +
+      'UnicodeEncodeError,UnicodeError,UnicodeTranslateError,UnicodeWarning,' +
+      'UserWarning,ValueError,Warning,ZeroDivisionError,_,__build_class__,' +
+      '__debug__,__doc__,__import__,__loader__,__name__,__package__,__spec__,' +
+      'abs,all,any,apply,ascii,basestring,bin,bool,buffer,bytearray,bytes,' +
+      'callable,chr,classmethod,cmp,coerce,compile,complex,copyright,credits,' +
+      'delattr,dict,dir,divmod,enumerate,eval,exec,execfile,exit,file,filter,' +
+      'float,format,frozenset,getattr,globals,hasattr,hash,help,hex,id,input,' +
+      'int,intern,isinstance,issubclass,iter,len,license,list,locals,long,' +
+      'map,max,memoryview,min,next,object,oct,open,ord,pow,print,property,' +
+      'quit,range,raw_input,reduce,reload,repr,reversed,round,set,setattr,' +
+      'slice,sorted,staticmethod,str,sum,super,tuple,type,unichr,unicode,' +
+      'vars,xrange,zip'
+    );
+  }
+  
+  /**
+   * Initialise the database of variable names.
+   * @param {!Workspace} workspace Workspace to generate code from.
+   * @this {CodeGenerator}
+   */
+  init(workspace) {
+    super.init(workspace);
+  
+    /**
+     * Empty loops or conditionals are not allowed in Python.
+     */
+    this.PASS = this.INDENT + 'pass\n';
+  
+    if (!this.nameDB_) {
+      this.nameDB_ = new Names(this.RESERVED_WORDS_);
+    } else {
+      this.nameDB_.reset();
+    }
+  
+    this.nameDB_.setVariableMap(workspace.getVariableMap());
+    this.nameDB_.populateVariables(workspace);
+    this.nameDB_.populateProcedures(workspace);
+  
+    const defvars = [];
+    // Add developer variables (not created or named by the user).
+    const devVarList = Variables.allDeveloperVariables(workspace);
+    for (let i = 0; i < devVarList.length; i++) {
+      defvars.push(
+          this.nameDB_.getName(devVarList[i], Names.DEVELOPER_VARIABLE_TYPE) +
+          ' = None');
+    }
+  
+    // Add user variables, but only ones that are being used.
+    const variables = Variables.allUsedVarModels(workspace);
+    for (let i = 0; i < variables.length; i++) {
+      defvars.push(
+          this.nameDB_.getName(variables[i].getId(), NameType.VARIABLE) +
+          ' = None');
+    }
+  
+    this.definitions_['variables'] = defvars.join('\n');
+    this.isInitialized = true;
+  }
+  
+  /**
+   * Prepend the generated code with import statements and variable definitions.
+   * @param {string} code Generated code.
+   * @return {string} Completed code.
+   */
+  finish(code) {
+    // Convert the definitions dictionary into a list.
+    const imports = [];
+    const definitions = [];
+    for (let name in this.definitions_) {
+      const def = this.definitions_[name];
+      if (def.match(/^(from\s+\S+\s+)?import\s+\S+/)) {
+        imports.push(def);
+      } else {
+        definitions.push(def);
+      }
+    }
+    // Call Blockly.CodeGenerator's finish.
+    code = super.finish(code);
+    this.isInitialized = false;
+  
+    this.nameDB_.reset();
+    const allDefs = imports.join('\n') + '\n\n' + definitions.join('\n\n');
+    return allDefs.replace(/\n\n+/g, '\n\n').replace(/\n*$/, '\n\n\n') + code;
+  }
+  
+  /**
+   * Naked values are top-level blocks with outputs that aren't plugged into
+   * anything.
+   * @param {string} line Line of generated code.
+   * @return {string} Legal line of code.
+   */
+  scrubNakedValue(line) {
+    return line + '\n';
+  }
+  
+  /**
+   * Encode a string as a properly escaped Python string, complete with quotes.
+   * @param {string} string Text to encode.
+   * @return {string} Python string.
+   * @protected
+   */
+  quote_(string) {
+    string = string.replace(/\\/g, '\\\\').replace(/\n/g, '\\\n');
+  
+    // Follow the CPython behaviour of repr() for a non-byte string.
+    let quote = '\'';
+    if (string.indexOf('\'') !== -1) {
+      if (string.indexOf('"') === -1) {
+        quote = '"';
+      } else {
+        string = string.replace(/'/g, '\\\'');
+      }
+    }
+    return quote + string + quote;
+  }
+  
+  /**
+   * Encode a string as a properly escaped multiline Python string, complete
+   * with quotes.
+   * @param {string} string Text to encode.
+   * @return {string} Python string.
+   * @protected
+   */
+  multiline_quote_(string) {
+    const lines = string.split(/\n/g).map(this.quote_);
+    // Join with the following, plus a newline:
+    // + '\n' +
+    return lines.join(' + \'\\n\' + \n');
+  }
+  
+  /**
+   * Common tasks for generating Python from blocks.
+   * Handles comments for the specified block and any connected value blocks.
+   * Calls any statements following this block.
+   * @param {!Block} block The current block.
+   * @param {string} code The Python code created for this block.
+   * @param {boolean=} opt_thisOnly True to generate code for only this statement.
+   * @return {string} Python code with comments and subsequent blocks added.
+   * @protected
+   */
+  scrub_(block, code, opt_thisOnly) {
+    let commentCode = '';
+    // Only collect comments for blocks that aren't inline.
+    if (!block.outputConnection || !block.outputConnection.targetConnection) {
+      // Collect comment for this block.
+      let comment = block.getCommentText();
+      if (comment) {
+        comment = stringUtils.wrap(comment, this.COMMENT_WRAP - 3);
+        commentCode += this.prefixLines(comment + '\n', '# ');
+      }
+      // Collect comments for all value arguments.
+      // Don't collect comments for nested statements.
+      for (let i = 0; i < block.inputList.length; i++) {
+        if (block.inputList[i].type === inputTypes.VALUE) {
+          const childBlock = block.inputList[i].connection.targetBlock();
+          if (childBlock) {
+            comment = this.allNestedComments(childBlock);
+            if (comment) {
+              commentCode += this.prefixLines(comment, '# ');
+            }
+          }
+        }
+      }
+    }
+    const nextBlock = block.nextConnection && block.nextConnection.targetBlock();
+    const nextCode = opt_thisOnly ? '' : this.blockToCode(nextBlock);
+    return commentCode + code + nextCode;
+  }
+  
+  /**
+   * Gets a property and adjusts the value, taking into account indexing.
+   * If a static int, casts to an integer, otherwise returns a code string.
+   * @param {!Block} block The block.
+   * @param {string} atId The property ID of the element to get.
+   * @param {number=} opt_delta Value to add.
+   * @param {boolean=} opt_negate Whether to negate the value.
+   * @return {string|number}
+   */
+  getAdjustedInt(block, atId, opt_delta, opt_negate) {
+    let delta = opt_delta || 0;
+    if (block.workspace.options.oneBasedIndex) {
+      delta--;
+    }
+    const defaultAtIndex = block.workspace.options.oneBasedIndex ? '1' : '0';
+    const atOrder = delta ? this.ORDER_ADDITIVE : this.ORDER_NONE;
+    let at = this.valueToCode(block, atId, atOrder) || defaultAtIndex;
+  
+    if (stringUtils.isNumber(at)) {
+      // If the index is a naked number, adjust it right now.
+      at = parseInt(at, 10) + delta;
+      if (opt_negate) {
+        at = -at;
+      }
+    } else {
+      // If the index is dynamic, adjust it in code.
+      if (delta > 0) {
+        at = 'int(' + at + ' + ' + delta + ')';
+      } else if (delta < 0) {
+        at = 'int(' + at + ' - ' + -delta + ')';
+      } else {
+        at = 'int(' + at + ')';
+      }
+      if (opt_negate) {
+        at = '-' + at;
+      }
+    }
+    return at;
+  }
+}
--- a/generators/python/text.js
+++ b/generators/python/text.js
@@ -13,16 +13,16 @@ goog.declareModuleId('Blockly.Python.texts');

 import * as stringUtils from '../../core/utils/string.js';
 import {NameType} from '../../core/names.js';
-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['text'] = function(block, generator) {
+export function text(block, generator) {
  // Text value.
  const code = generator.quote_(block.getFieldValue('TEXT'));
  return [code, Order.ATOMIC];
 };

-pythonGenerator.forBlock['text_multiline'] = function(block, generator) {
+export function text_multiline(block, generator) {
  // Text value.
  const code = generator.multiline_quote_(block.getFieldValue('TEXT'));
  const order =
@@ -50,7 +50,7 @@ const forceString = function(value) {
  return ['str(' + value + ')', Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_join'] = function(block, generator) {
+export function text_join(block, generator) {
  // Create a string made up of any number of elements of any type.
  // Should we allow joining by '-' or ',' or any other characters?
  switch (block.itemCount_) {
@@ -85,7 +85,7 @@ pythonGenerator.forBlock['text_join'] = function(block, generator) {
  }
 };

-pythonGenerator.forBlock['text_append'] = function(block, generator) {
+export function text_append(block, generator) {
  // Append to a variable in place.
  const varName =
      generator.nameDB_.getName(
@@ -94,20 +94,20 @@ pythonGenerator.forBlock['text_append'] = function(block, generator) {
  return varName + ' = str(' + varName + ') + ' + forceString(value)[0] + '\n';
 };

-pythonGenerator.forBlock['text_length'] = function(block, generator) {
+export function text_length(block, generator) {
  // Is the string null or array empty?
  const text = generator.valueToCode(block, 'VALUE', Order.NONE) || "''";
  return ['len(' + text + ')', Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_isEmpty'] = function(block, generator) {
+export function text_isEmpty(block, generator) {
  // Is the string null or array empty?
  const text = generator.valueToCode(block, 'VALUE', Order.NONE) || "''";
  const code = 'not len(' + text + ')';
  return [code, Order.LOGICAL_NOT];
 };

-pythonGenerator.forBlock['text_indexOf'] = function(block, generator) {
+export function text_indexOf(block, generator) {
  // Search the text for a substring.
  // Should we allow for non-case sensitive???
  const operator = block.getFieldValue('END') === 'FIRST' ? 'find' : 'rfind';
@@ -122,7 +122,7 @@ pythonGenerator.forBlock['text_indexOf'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_charAt'] = function(block, generator) {
+export function text_charAt(block, generator) {
  // Get letter at index.
  // Note: Until January 2013 this block did not have the WHERE input.
  const where = block.getFieldValue('WHERE') || 'FROM_START';
@@ -163,7 +163,7 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(text):
  throw Error('Unhandled option (text_charAt).');
 };

-pythonGenerator.forBlock['text_getSubstring'] = function(block, generator) {
+export function text_getSubstring(block, generator) {
  // Get substring.
  const where1 = block.getFieldValue('WHERE1');
  const where2 = block.getFieldValue('WHERE2');
@@ -213,7 +213,7 @@ pythonGenerator.forBlock['text_getSubstring'] = function(block, generator) {
  return [code, Order.MEMBER];
 };

-pythonGenerator.forBlock['text_changeCase'] = function(block, generator) {
+export function text_changeCase(block, generator) {
  // Change capitalization.
  const OPERATORS = {
    'UPPERCASE': '.upper()',
@@ -226,7 +226,7 @@ pythonGenerator.forBlock['text_changeCase'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_trim'] = function(block, generator) {
+export function text_trim(block, generator) {
  // Trim spaces.
  const OPERATORS = {
    'LEFT': '.lstrip()',
@@ -239,13 +239,13 @@ pythonGenerator.forBlock['text_trim'] = function(block, generator) {
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_print'] = function(block, generator) {
+export function text_print(block, generator) {
  // Print statement.
  const msg = generator.valueToCode(block, 'TEXT', Order.NONE) || "''";
  return 'print(' + msg + ')\n';
 };

-pythonGenerator.forBlock['text_prompt_ext'] = function(block, generator) {
+export function text_prompt_ext(block, generator) {
  // Prompt function.
  const functionName = generator.provideFunction_('text_prompt', `
 def ${generator.FUNCTION_NAME_PLACEHOLDER_}(msg):
@@ -270,17 +270,16 @@ def ${generator.FUNCTION_NAME_PLACEHOLDER_}(msg):
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_prompt'] =
-    pythonGenerator.forBlock['text_prompt_ext'];
+export const text_prompt = text_prompt_ext;

-pythonGenerator.forBlock['text_count'] = function(block, generator) {
+export function text_count(block, generator) {
  const text = generator.valueToCode(block, 'TEXT', Order.MEMBER) || "''";
  const sub = generator.valueToCode(block, 'SUB', Order.NONE) || "''";
  const code = text + '.count(' + sub + ')';
  return [code, Order.FUNCTION_CALL];
 };

-pythonGenerator.forBlock['text_replace'] = function(block, generator) {
+export function text_replace(block, generator) {
  const text = generator.valueToCode(block, 'TEXT', Order.MEMBER) || "''";
  const from = generator.valueToCode(block, 'FROM', Order.NONE) || "''";
  const to = generator.valueToCode(block, 'TO', Order.NONE) || "''";
@@ -288,7 +287,7 @@ pythonGenerator.forBlock['text_replace'] = function(block, generator) {
  return [code, Order.MEMBER];
 };

-pythonGenerator.forBlock['text_reverse'] = function(block, generator) {
+export function text_reverse(block, generator) {
  const text = generator.valueToCode(block, 'TEXT', Order.MEMBER) || "''";
  const code = text + '[::-1]';
  return [code, Order.MEMBER];
--- a/generators/python/variables.js
+++ b/generators/python/variables.js
@@ -12,10 +12,10 @@ import * as goog from '../../closure/goog/goog.js';
 goog.declareModuleId('Blockly.Python.variables');

 import {NameType} from '../../core/names.js';
-import {pythonGenerator, Order} from '../python.js';
+import {Order} from './python_generator.js';


-pythonGenerator.forBlock['variables_get'] = function(block, generator) {
+export function variables_get(block, generator) {
  // Variable getter.
  const code =
      generator.nameDB_.getName(
@@ -23,7 +23,7 @@ pythonGenerator.forBlock['variables_get'] = function(block, generator) {
  return [code, Order.ATOMIC];
 };

-pythonGenerator.forBlock['variables_set'] = function(block, generator) {
+export function variables_set(block, generator) {
  // Variable setter.
  const argument0 =
      generator.valueToCode(block, 'VALUE', Order.NONE) || '0';
--- a/generators/python/variables_dynamic.js
+++ b/generators/python/variables_dynamic.js
@@ -11,10 +11,9 @@
 import * as goog from '../../closure/goog/goog.js';
 goog.declareModuleId('Blockly.Python.variablesDynamic');

-import {pythonGenerator} from '../python.js';
-import './variables.js';
-

 // generator is dynamically typed.
-pythonGenerator.forBlock['variables_get_dynamic'] = pythonGenerator.forBlock['variables_get'];
-pythonGenerator.forBlock['variables_set_dynamic'] = pythonGenerator.forBlock['variables_set'];
+export {
+  variables_get as variables_get_dynamic,
+  variables_set as variables_set_dynamic,
+} from './variables.js';