[Indigo]<AlgebraStructures>NewAlgebraStructures>ASSequenceStructure.mesa!1

Sequences.mesa

Last Edited by: Arnon, May 3, 1986 3:53:47 pm PDT

Variable-length sequences of elements of some elementStructure.

DIRECTORY

Rope,

IO,

AlgebraClasses;

Sequences: CEDAR DEFINITIONS

~ BEGIN OPEN Rope, AC: AlgebraClasses;

Sequence Representation

Sequence: TYPE = AC.Object;

SequenceData: TYPE = REF SequenceDataRec;

SequenceDataRec: TYPE = RECORD [

SEQUENCE lengthPlus1:[1..65534] OF AC.Object

];

An empty sequence is represented with non-NIL data field consisting of a SequenceDataRec of length 0.

Instance Data for Sequence Structures

SequenceStructureData: TYPE = REF SequenceStructureDataRec;

SequenceStructureDataRec: TYPE = RECORD [

row: BOOL ← TRUE,

elementStructure: AC.Object

];

Sequence Structure Ops

MakeSequenceStructure: AC.SequenceStructureConstructor;

PrintName: AC.ToRopeOp;

ShortPrintName: AC.ToRopeOp;

ElementStructure: AC.UnaryOp;

Conversion and IO

Recast: AC.BinaryOp;

CanRecast: AC.BinaryPredicate;

ToExpr: AC.ToExprOp;

LegalFirstChar: AC.LegalFirstCharOp;

Read: AC.ReadOp;

FromRope: AC.FromRopeOp;

ToRope: AC.ToRopeOp;

Write: AC.WriteOp;

Constructor

MakeSequence: AC.ListImbedOp;

Attempts to recast supplied elements into elementStructure.

If data = NIL then returns a Sequence whose SequenceDataRec is of length 0.

Selection

Select: AC.BinaryOp;

firstArg is a Sequence, secondArg is an Ints.Int specifying position to select. Returns NIL if can't do.

First: AC.UnaryOp;

firstArg = Sequence, return first element. Return NIL if empty.

Last: AC.UnaryOp;

firstArg = Sequence, return last element. Return NIL if empty.

Length: AC.ElementRankOp;

Predicates

IsSubset: AC.BinaryPredicate;

firstArg and secondArg are Sequences. Returns TRUE if firstArg is a subset of secondArg. Returns FALSE if args have different elementStructures.

Subsequence: AC.BinaryPredicate;

firstArg and secondArg are Sequences. Returns TRUE if firstArg is a subsequence of secondArg. Returns FALSE if args have different elementStructures.

Operations

Equal: AC.BinaryPredicate;

Prepend: AC.BinaryOp;

firstArg = Sequence, secondArg = new Item. Place secondArg at the beginning of firstArg. secondArg must belong to firstArg's elementStructure.

Append: AC.BinaryOp;

firstArg = Sequence, secondArg = new Item. Place secondArg at the end of firstArg. secondArg must belong to firstArg's elementStructure.

Insert: AC.TernaryOp;

firstArg is a Sequence, secondArg is an Ints.Int specifying position after which to insert new item, thirdArg is new item. secondArg = 0 means insert at beginning, secondArg = i means insert after ith element of sequence. thirdArg must belong to firstArg's elementStructure.

Error if secondArg > Length[firstArg].

Delete: AC.BinaryOp;

firstArg is a Sequence, secondArg is a positive Ints.Int specifying position to delete.

Error if secondArg<1 OR secondArg > Length[firstArg].

DeleteLast: AC.UnaryOp;

firstArg is a Sequence. If length = 0, noOp.

Find: AC.BinaryOp;

firstArg is a Sequence, secondArg is an element of the Sequence's elementStructure. Returns an Ints.Int giving position of secondArg in firstArg if found, else returns NIL

Concatenate: AC.BinaryOp;

Concatenate two Sequences. Must have same elementStructure.

MapUnaryElementOp: AC.BinaryMixedOp;

firstArg is a Sequence, secondArg is a unary Method (e.g. UnaryOp, UnaryPredicate) on its elementStructure, result is Sequence of results of applications of the unary operation to the elements of firstArg.

FilterByUnaryPredicate: AC.BinaryMixedOp;

firstArg is a Sequence, secondArg is a UnaryPredicate on its elementStructure, result is subSequence of elements of firstArg which satisfy the predicate.

MapBinaryElementOp: AC.TernaryMixedOp;

firstArg and secondArg are Sequences over the same elementStructure, and of the same length. thirdArg is a binary Method (e.g. BinaryOp, BinaryPredicate) on elementStructure. The result is a Sequence of the results of the application of the binary operation to corresponding pairs of elements of firstArg and secondArg.

END.