org.stekikun.dolmen.syntax

Class Lexer.Entry

java.lang.Object

org.stekikun.dolmen.syntax.Lexer.Entry

Enclosing class:

Lexer

public static final class Lexer.Entry
extends Object

A lexer rule entry is a sequence of regular expressions associated to semantic actions. A rule has a name, a return type and may have some arguments. The regular expressions that form the rule are called the clauses and are normally interpreted with the longest match priority, unless specified otherwise.

NB: In state-based lexer generators like JLex or JavaCC, the equivalent of a lexer rule entry is a lexer state along with all the rules that apply to this state. The equivalent of changing lexer state when matching a regular expression is to call the corresponding rule in the semantic action.

Author:

Stéphane Lescuyer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Lexer.Entry.Builder A builder class for lexer entries, which lets one add clauses incrementally

Field Summary

Fields

Modifier and Type	Field and Description
@Nullable Extent	args The formal arguments for this rule
List<Lexer.Clause>	clauses The various clauses for this entry, associated to the extents for the corresponding semantic actions.
Located<String>	name The name of this entry
Extent	returnType The return type of semantic actions for this entry
boolean	shortest Whether shortest match should be used
boolean	visibility The visibility of this entry point

Constructor Summary

Constructors

Constructor and Description
Entry(boolean visibility, Located<String> name, Extent returnType, boolean shortest, @Nullable Extent args, List<Lexer.Clause> clauses)

Method Summary

Modifier and Type	Method and Description
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

visibility

public final boolean visibility

The visibility of this entry point

name

public final Located<String> name

The name of this entry

shortest

public final boolean shortest

Whether shortest match should be used

args

public final @Nullable Extent args

The formal arguments for this rule

returnType

public final Extent returnType

The return type of semantic actions for this entry

clauses

public final List<Lexer.Clause> clauses

The various clauses for this entry, associated to the extents for the corresponding semantic actions. Iteration order in clauses is relevant as priority between same-length matches goes to the first matching rule in this map.

Constructor Detail

Entry

public Entry(boolean visibility,
             Located<String> name,
             Extent returnType,
             boolean shortest,
             @Nullable Extent args,
             List<Lexer.Clause> clauses)

Parameters:

visibility -

name -

returnType -

shortest -

args -

clauses - Builds a new lexer entry with the provided arguments. Beware that order in clauses is relevant.

Method Detail

toString

public String toString()

Overrides:

toString in class Object