Class: Generator

Constructor

Generator

new Generator(name)

Class for a code generator that translates the blocks into a language.

Parameter

name

string

Language name of this generator.

Properties

NAME_TYPE

static

Category to separate generated function names from variables and procedures.

COMMENT_WRAP

number

Maximum length for a comment before wrapping. Does not account for indenting level.

definitions_

protected

Object

A dictionary of definitions to be printed before the code.

FUNCTION_NAME_PLACEHOLDER_

protected

string

This is used as a placeholder in functions defined using Blockly.Generator.provideFunction_. It must not be legal code that could legitimately appear in a function definition (or comment), and it must not confuse the regular expression parser.

functionNames_

protected

Object

A dictionary mapping desired function names in definitions_ to actual function names (to avoid collisions with user functions).

INDENT

string

The method of indenting. Defaults to two spaces, but language generators may override this to increase indent or change to tabs.

INFINITE_LOOP_TRAP

nullable string

Arbitrary code to inject into locations that risk causing infinite loops. Any instances of '%1' will be replaced by the block ID that failed. E.g. ' checkTimeout(%1);\n'

ORDER_OVERRIDES

non-null Array of non-null Array of number

List of outer-inner pairings that do NOT require parentheses.

RESERVED_WORDS_

protected

string

Comma-separated list of reserved words.

STATEMENT_PREFIX

nullable string

Arbitrary code to inject before every statement. Any instances of '%1' will be replaced by the block ID of the statement. E.g. 'highlight(%1);\n'

STATEMENT_SUFFIX

nullable string

Arbitrary code to inject after every statement. Any instances of '%1' will be replaced by the block ID of the statement. E.g. 'highlight(%1);\n'

variableDB_

protected

Blockly.Names

A database of variable names.

Methods

addLoopTrap

addLoopTrap(branch, block) returns string

Add an infinite loop trap to the contents of a loop. Add statement suffix at the start of the loop block (right after the loop statement executes), and a statement prefix to the end of the loop block (right before the loop statement executes).

Parameter

branch

string

Code for loop contents.

block

Blockly.Block

Enclosing block.

Value must not be null.

Returns

string Loop contents, with infinite loop trap added.

addReservedWords

addReservedWords(words)

Add one or more words to the list of reserved words for this language.

Parameter

words

string

Comma-separated list of words to add to the list. No spaces. Duplicates are ok.

allNestedComments

allNestedComments(block) returns string

Recursively spider a tree of blocks, returning all their comments.

Parameter

block

Blockly.Block

The block from which to start spidering.

Value must not be null.

Returns

string Concatenated list of comments.

blockToCode

blockToCode(block, opt_thisOnly) returns (string or Array)

Generate code for the specified block (and attached blocks).

Parameter

block

Blockly.Block

The block to generate code for.

opt_thisOnly

Optional

boolean

True to generate code for only this statement.

Returns

(string or non-null Array) For statement blocks, the generated code. For value blocks, an array containing the generated code and an operator order value. Returns '' if block is null.

finish

finish(code) returns string

Hook for code to run at end of code generation. Subclasses may override this, e.g. to prepend the generated code with the variable definitions.

Parameter

code

string

Generated code.

Returns

string Completed code.

init

init(_workspace)

Hook for code to run before code generation starts. Subclasses may override this, e.g. to initialise the database of variable names.

Parameter

_workspace

Blockly.Workspace

Workspace to generate code from.

Value must not be null.

injectId

injectId(msg, block) returns string

Inject a block ID into a message to replace '%1'. Used for STATEMENT_PREFIX, STATEMENT_SUFFIX, and INFINITE_LOOP_TRAP.

Parameter

msg

string

Code snippet with '%1'.

block

Blockly.Block

Block which has an ID.

Value must not be null.

Returns

string Code snippet with ID.

prefixLines

prefixLines(text, prefix) returns string

Prepend a common prefix onto each line of code. Intended for indenting code or adding comment markers.

Parameter

text

string

The lines of code.

prefix

string

The common prefix.

Returns

string The prefixed lines of code.

provideFunction_

protected

provideFunction_(desiredName, code) returns string

Define a function to be included in the generated code. The first time this is called with a given desiredName, the code is saved and an actual name is generated. Subsequent calls with the same desiredName have no effect but have the same return value.

It is up to the caller to make sure the same desiredName is not used for different code values.

The code gets output when Blockly.Generator.finish() is called.

Parameter

desiredName

string

The desired name of the function (e.g., isPrime).

code

Array of string

A list of statements. Use ' ' for indents.

Value must not be null.

Returns

string The actual name of the new function. This may differ from desiredName if the former has already been taken by the user.

scrub_

protected

scrub_(_block, code, _opt_thisOnly) returns string

Common tasks for generating code from blocks. This is called from blockToCode and is called on every block, not just top level blocks. Subclasses may override this, e.g. to generate code for statements following the block, or to handle comments for the specified block and any connected value blocks.

Parameter

_block

Blockly.Block

The current block.

Value must not be null.

code

string

The code created for this block.

_opt_thisOnly

Optional

boolean

True to generate code for only this statement.

Returns

string Code with comments and subsequent blocks added.

scrubNakedValue

scrubNakedValue(line) returns string

Naked values are top-level blocks with outputs that aren't plugged into anything. Subclasses may override this, e.g. if their language does not allow naked values.

Parameter

line

string

Line of generated code.

Returns

string Legal line of code.

statementToCode

statementToCode(block, name) returns string

Generate a code string representing the blocks attached to the named statement input. Indent the code. This is mainly used in generators. When trying to generate code to evaluate look at using workspaceToCode or blockToCode.

Parameter

block

Blockly.Block

The block containing the input.

Value must not be null.

name

string

The name of the input.

Returns

string Generated code or '' if no blocks are connected.

valueToCode

valueToCode(block, name, outerOrder) returns string

Generate code representing the specified value input.

Parameter

block

Blockly.Block

The block containing the input.

Value must not be null.

name

string

The name of the input.

outerOrder

number

The maximum binding strength (minimum order value) of any operators adjacent to "block".

Returns

string Generated code or '' if no blocks are connected or the specified input does not exist.

workspaceToCode

workspaceToCode(workspace) returns string

Generate code for all blocks in the workspace to the specified language.

Parameter

workspace

Blockly.Workspace

Workspace to generate code from.

Returns

string Generated code.