abstract classafPegger::Rule

sys::Obj
  afPegger::Rule

@Js

(Advanced) Models a PEG Rule.

Rules are commonly created by using methods from the Rules mixin, but may be parsed from string patterns.

Rule may sub-classed to create your own custom rules.

debug

Source

virtual Bool debug := true

Disable debugging of this rule if it gets too noisy.

debugOff

Source

This debugOff()

A helpful builder method for turning debug off.

definition

Source

Str definition()

Returns the PEG definition for this rule. Example:

alphaNum <- [a-zA-Z0-9]

excludeFromResults

Source

This excludeFromResults()

A helpful builder method for removing this rule from tree results.

expression

Source

abstract Str expression()

Returns the PEG expression for this rule. Example:

[a-zA-Z0-9]

label

Source

virtual Str? label

A label for this rule. Only rules with labels appear in the output tree.

Should be legal Fantom identifier (think variable names!).

match

Source

Match? match(Str str)

Matches this rule against the given string.

See Peg.match

name

Source

virtual Str? name

The name of this rule. Only rules with names appear in debug output.

Should be legal Fantom identifier (think variable names!).

parseRule

Source

static new parseRule(Str pattern)

Creates a rule by parsing the given pattern:

Rule.fromPattern("[abc] / [xyz]")

See Peg.parseRule

useInResult

Source

virtual Bool useInResult := true

Not all rules are useful in the parsed AST.

withLabel

Source

This withLabel(Str? label)

A helpful builder method for setting the label. Only rules with labels appear in the output tree.

withName

Source

This withName(Str? name)

A helpful builder method for setting the name.

Only rules with names appear in debug output.