org.quasiliteral.text
Class Substituter

java.lang.Object
  |
  +--org.quasiliteral.text.Substituter

All Implemented Interfaces:

MatchMaker, ValueMaker

public class Substituter

extends Object

implements ValueMaker, MatchMaker

Safe: The default -- and simplest -- of the quasi parsers

Author:

Mark S. Miller

Field Summary

private int	myMatchSize
private Object[]	myTemplate A template is "compiled" into an array of three kinds of elements:

Constructor Summary

(package private)

Substituter(Twine template)

Method Summary

private static boolean	isDigit(char c)
ConstList	matchBind(ConstList args, Object specimen) Enabled: As a quasi-pattern, "first" replace all ${i}s with args[i]s, then see if the speciman matches the pattern.
boolean	matchBind(ConstList args, Object specimen, FlexList bindings) Enabled:
int	numArgs() Enabled: The number of arguments that must be provided to substitute() or matchBind()
int	numPatterns() Enabled: The number of bindings that will be returned by matchBind()
private Twine	optSegments(int[] iPtr, ConstList args) If the iPtr[0]'th segment is a pattern, then return null and leave iPtr alone.
private ConstList	optSequence(int[] iPtr, ConstList args) If the iPtr[0]'th segment is a pattern, then return null and leave iPtr alone.
Object	substitute(ConstList args) Enabled: Evaluate as a quasi-literal by replacing ${i} with args[i], for all i
String	toString() Suppressed: Prints using the template string

Methods inherited from class java.lang.Object

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

Field Detail

myTemplate

private Object[] myTemplate

A template is "compiled" into an array of three kinds of elements:

A Twine represents a literal string segment.

A positive Integer represents a position into which to substitute an arg.

A negative Integer represents a pattern position (XXX needs a real explanation).

XXX this representation is a kludge

myMatchSize

private int myMatchSize

Constructor Detail

Substituter

Substituter(Twine template)

Method Detail

isDigit

private static boolean isDigit(char c)

matchBind

public ConstList matchBind(ConstList args,
                           Object specimen)

Enabled: As a quasi-pattern, "first" replace all ${i}s with args[i]s, then see if the speciman matches the pattern. If not, return null. If so, return an array in which the i'th element is the part of the specimen that matched @{i}.

Specified by:

matchBind in interface MatchMaker

matchBind

public boolean matchBind(ConstList args,
                         Object specimen,
                         FlexList bindings)

Enabled:

Specified by:

matchBind in interface MatchMaker

optSequence

private ConstList optSequence(int[] iPtr,
                              ConstList args)

If the iPtr[0]'th segment is a pattern, then return null and leave iPtr alone. Otherwise, return the string gotten by appending the consecutive non-pattern segments starting with the iPtr[0]'th segment, and modify iPtr[0] to be the following segment number.

optSegments

private Twine optSegments(int[] iPtr,
                          ConstList args)

If the iPtr[0]'th segment is a pattern, then return null and leave iPtr alone. Otherwise, return the string gotten by appending the consecutive non-pattern segments starting with the iPtr[0]'th segment, and modify iPtr[0] to be the following segment number.

substitute

public Object substitute(ConstList args)

Enabled: Evaluate as a quasi-literal by replacing ${i} with args[i], for all i

Specified by:

substitute in interface ValueMaker

numArgs

public int numArgs()

Enabled: The number of arguments that must be provided to substitute() or matchBind()

numPatterns

public int numPatterns()

Enabled: The number of bindings that will be returned by matchBind()

toString

public String toString()

Suppressed: Prints using the template string

Overrides:

toString in class Object

Returns:

a string representation of the object.