orc.ast.extended.pattern
Class Pattern

java.lang.Object
  orc.ast.extended.pattern.Pattern

Direct Known Subclasses:

AsPattern, CallPattern, ConsPattern, ListPattern, LiteralPattern, NilPattern, PublishPattern, TuplePattern, VariablePattern, WildcardPattern

public abstract class Pattern
extends java.lang.Object

Base interface for the abstract syntax of patterns. Patterns exist only in the extended abstract syntax. They desugar into a series of operations which terminate in variable bindings.

Author:

dkitchin

Field Summary

protected static Argument	CONS
protected static Argument	EQUAL
protected static Argument	HEAD
protected static Argument	IF
protected static Argument	ISCONS
protected static Argument	ISNIL
static Argument	ISNONE
static Argument	ISSOME
protected static Argument	NONE
protected static Argument	NOT
protected static Argument	SOME
protected static Argument	TAIL

Constructor Summary

Pattern()

Method Summary

Expression	bind(Expression f, Expression g)
abstract Expression	bind(Var u, Expression g)
static Expression	filter(Expression e) Filter an expression by piping its publications through isSome.
static Expression	ifexp(Expression test, Expression tc, Expression fc)
static Expression	lift(java.util.List<Expression> es) Lifted application of a site to a list of optional arguments.
Expression	match(Expression f)
abstract Expression	match(Var u)
static Expression	opbind(Expression f, Var t, Expression g) Create an expression computing a monadic bind for options.
boolean	strict()

Methods inherited from class java.lang.Object

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

Field Detail

IF

protected static Argument IF

NOT

protected static Argument NOT

SOME

protected static Argument SOME

NONE

protected static Argument NONE

ISSOME

public static Argument ISSOME

ISNONE

public static Argument ISNONE

CONS

protected static Argument CONS

ISCONS

protected static Argument ISCONS

ISNIL

protected static Argument ISNIL

HEAD

protected static Argument HEAD

TAIL

protected static Argument TAIL

EQUAL

protected static Argument EQUAL

Constructor Detail

Pattern

public Pattern()

Method Detail

match

public abstract Expression match(Var u)

Parameters:

f - The source expression for values to be matched

Returns:

A new expression publishing, for each publication !v of f,

 some(v')       if p(v) => v' 
 none           if p(v) => _|_
 

bind

public abstract Expression bind(Var u,
                                Expression g)

match

public Expression match(Expression f)

bind

public Expression bind(Expression f,
                       Expression g)

strict

public boolean strict()

ifexp

public static Expression ifexp(Expression test,
                               Expression tc,
                               Expression fc)

lift

public static Expression lift(java.util.List<Expression> es)

Lifted application of a site to a list of optional arguments. If every argument evaluates to some(vi), then the result is some(C(v1,...,vn)). If any argument evaluates to none, the result is none. lift(e1...en) = ( some(s1, ... , sn) .. > none()

opbind

public static Expression opbind(Expression f,
                                Var t,
                                Expression g)

Create an expression computing a monadic bind for options. I'd really rather be using Haskell here.

opbind(f,t,g) = f >s> ( (isSome(s) >t> g) >u> some(u) | isNone(s) >> none )

filter

public static Expression filter(Expression e)

Filter an expression by piping its publications through isSome. Values some(v) will publish v, values none will be ignored.

Parameters:

e -