[Cyan]<CedarChest6.0>RegularExpression>RegularExpression.mesa!1

RegularExpression.mesa

Nix, December 20, 1983 2:39 pm

Russ Atkinson (RRA) April 25, 1985 5:26:16 am PST

DIRECTORY

TextLooks USING [Looks, Runs],

RunReader USING [Ref],

LooksReader USING [Ref],

TextNode USING [Offset, RefTextNode],

Rope USING [ROPE],

RopeReader USING [Ref];

RegularExpression: CEDAR DEFINITIONS = {

Operations & types stolen from TextFind

MalformedPattern: ERROR [ec: PatternErrorCode];

PatternErrorCode: TYPE = {

toobig, -- pattern too long

endquote, -- pattern ends with '

endtilda, -- pattern ends with ~

boundary, -- pattern has | inside rather than at beginning or end

missingNameEnd, -- pattern has < without matching >

unmatchedNameEnd -- pattern has > without previous <

};

RefTextNode: TYPE = TextNode.RefTextNode;

Operations stolen from TextFind, exported from RegExpFindImpl

Create: PROC [pattern: RefTextNode,
literal, word, ignoreLooks, ignoreCase, addBounds: BOOL ← FALSE,
patternStart: INT ← 0, patternLen: INT ← LAST[INT]] RETURNS [finder: Finder];

creates a record containing a "compiled" version of the pattern

if literal is true, each character in pattern is taken literally

if word flag is true, pattern only matches if no adjacent letters or digits

if ignoreLooks is true, then ignore the looks of the pattern characters

if ignoreCase is false, then alpha chars in pattern must match case

otherwise, they can match either upper or lower

if addBounds is true, add |'s to both ends of pattern

CreateFromRope: PROC [pattern: ROPE,
literal, word, ignoreCase, addBounds: BOOL ← FALSE,
patternStart: INT ← 0, patternLen: INT ← LAST[INT]] RETURNS [finder: Finder];

NameLooks: PROC [finder: Finder, name: ROPE] RETURNS [looks: TextLooks.Looks];

name is the name of a subpattern

value are looks that name had in the pattern

NameLoc: PROC [finder: Finder, name: ROPE] RETURNS [at, atEnd: INT];

name is the name of a subpattern

value is where that subpattern matched last time

Operations stolen from TextFind, exported from RegExpFind2Impl

SearchRope: PROC [finder: Finder, rope: ROPE, start: INT ← 0, len: INT ← LAST[INT],
interrupt: REF BOOL ← NIL] RETURNS [found: BOOL, at, atEnd, before, after: INT];

Try: PROC [finder: Finder, text: RefTextNode,
start: INT ← 0, len: INT ← LAST[INT], looksExact: BOOL ← FALSE,
interrupt: REF BOOL ← NIL] RETURNS [found: BOOL, at, atEnd, before, after: INT];

searches text for first match in [start..start+len)

i.e., searches up from start until reaches start+len

if finds a match, returns with found = true,

at = beginning of match or location corresponding to { in pattern

atEnd = end of match or location corresponding to } in pattern

after = end of entire match, which may be > atEnd if used } in pattern

before = start of entire match, which may be < at if used { in pattern

if looksExact is true, then match by equality, else by subset

if interrupt^ becomes true, will stop searching

SearchRopeBackwards: PROC [finder: Finder, rope: ROPE, start: INT ← 0, len: INT ← LAST[INT], interrupt: REF BOOL ← NIL] RETURNS [found: BOOL, at, atEnd, before, after: INT];

TryBackwards: PROC [finder: Finder, text: RefTextNode,
start: INT ← 0, len: INT ← LAST[INT], looksExact: BOOL ← FALSE,
interrupt: REF BOOL ← NIL] RETURNS [found: BOOL, at, atEnd, before, after: INT];

searches text for last match in [start..start+len)

i.e., searches down from start+len until reaches start

Operations

Search: PUBLIC PROC [finder: Finder, rope: ROPE, runs: TextLooks.Runs, start: Offset, len: Offset, looksExact: BOOL, interrupt: REF BOOL ← NIL] RETURNS [found: BOOL, at, atEnd, before, after: Offset];

OptimizeForwardSearch: PROC[p: ParseTree, ccl: LIST OF ParseTree, numCcl: Index] RETURNS [np: ParseTree, newCcl: LIST OF ParseTree, newNumCcl: Index];

OptimizeBackwardSearch: PROC[p: ParseTree, ccl: LIST OF ParseTree, numCcl: Index] RETURNS [np: ParseTree, newCcl: LIST OF ParseTree, newNumCcl: Index];

Compile: PROC [p: ParseTree] RETURNS [c: Code];

Types

ROPE: TYPE = Rope.ROPE;

Offset: TYPE = TextNode.Offset;

CharClassContent: TYPE = PACKED ARRAY LegalCharacters OF BOOL;

CharClass: TYPE = REF CharClassContent;

Index: TYPE = NAT;

IgnoreLooks: TextLooks.Looks = ALL[TRUE]; -- A bogus definition, but it'll work.

ParseTypes: TYPE = {

concat,

char, charIC, class, anyChar,

nodeBreak, skipToNodeBreak,

beginNode, skipToBeginNode,

fail, succeed, noOp,

skipOverClass, skipOverChar, skipOverCharIC, skipOver,

skipToChar, skipToCharIC, skipToString, skipTo,

skipToEnd, skipToBeginning,

closure, carefulClosure, greedyClosure, carefulGreedyClosure, alt,

field, fieldEquals, fieldEqualsIC, beginAll, endAll, beginALL, endALL};

ParseTreeContent: TYPE = RECORD[

SELECT type: ParseTypes FROM

concat => [concats: LIST OF ParseTree],

char, charIC => [char: CHAR, looks: TextLooks.Looks],

class => [class: CharClass, looks: TextLooks.Looks, classNumber: Index],

anyChar => [looks: TextLooks.Looks],

nodeBreak => NULL,

skipToNodeBreak => [looks: TextLooks.Looks],

beginNode => NULL,

skipToBeginNode => NULL,

fail, succeed, noOp => NULL,

skipOverClass => [class: CharClass, looks: TextLooks.Looks, classNumber: Index],

skipOverChar, skipOverCharIC => [char: CHAR, looks: TextLooks.Looks],

skipOver => [p: ParseTree],

skipToChar, skipToCharIC => [char: CHAR, looks: TextLooks.Looks],

skipToString => [p: ParseTree],

skipTo => [p: ParseTree],

skipToEnd, skipToBeginning => NULL,

closure, carefulClosure, greedyClosure, carefulGreedyClosure => [p: ParseTree],

alt => [alts: LIST OF ParseTree],

field => [number: Index, bound: INT, p: ParseTree],

fieldEquals, fieldEqualsIC => [number: Index],

beginAll, endAll, beginALL, endALL => NULL

ENDCASE

];

ParseTree: TYPE = REF ParseTreeContent;

EightBit: CHAR = 200C;

CharMask: CHAR = 177C;

LegalCharacters: TYPE = CHAR[0C..177C];

LegalInputCharacters: TYPE = CHAR[1C..177C];

beginClassToken: CHAR = EightBit + 1; -- [

endClassToken: CHAR = EightBit + 2; -- ]

notToken: CHAR = EightBit + 3; -- ~

anyToken: CHAR = EightBit + 4; -- #

nodeBreakToken: CHAR = EightBit + 5; -- $

closureToken: CHAR = EightBit + 6; -- *

greedyClosureToken: CHAR = EightBit + 7; -- **

plusToken: CHAR = EightBit + 8; -- +

greedyPlusToken: CHAR = EightBit + 9; -- ++

beginAltToken: CHAR = EightBit + 10; -- (

endAltToken: CHAR = EightBit + 11; -- )

altSepToken: CHAR = EightBit + 12; -- |

beginFieldToken: CHAR = EightBit + 13; -- <

endFieldToken: CHAR = EightBit + 14; -- >

fieldSepToken: CHAR = EightBit + 15; -- :

boundSepToken: CHAR = EightBit + 16; -- ,

endPatternToken: CHAR = EightBit + 17; -- end of Pattern.

beginAllToken: CHAR = EightBit + 19; -- {

endAllToken: CHAR = EightBit + 20; -- }

subRangeToken: CHAR = EightBit + 21; -- ..

beginNodeToken: CHAR = EightBit +22; -- ^

powerToken: CHAR = EightBit +23; -- !

OpCode: TYPE = {

matchChar, matchCharIC, matchCharLooks, matchCharLooksIC,

matchClass, matchClassLooks,

matchAnyChar, matchAnyCharLooks,

matchNodeBreak, skipToNodeBreak, skipToNodeBreakLooks,

matchBeginNode,

fail, succeed, noOp,

skipOverClass, skipOverClassLooks,

skipOverChar, skipOverCharLooks,

skipOverCharIC, skipOverCharLooksIC,

skipToChar, skipToCharLooks,

skipToCharIC, skipToCharLooksIC,

skipToString, endOfSkipToString,

skipToEnd, skipToBeginning,

closure, carefulClosure, carefulClosureEnd,

greedyClosure, carefulGreedyClosure, carefulGreedyClosureEnd, alt,

fieldStart, fieldEnd, boundNodeBreaks,

fieldEquals, fieldEqualsLooks, fieldEqualsIC, fieldEqualsLooksIC,

beginAll, endAll

};

ReturnCode: TYPE = {skipToStringRet, closureRet, carefulClosureRet, greedyClosureRet, carefulGreedyClosureRet, altRet};

PatternPC: TYPE = NAT;

TextStackArray: TYPE = RECORD[stack: SEQUENCE length: NAT OF Offset];

PatternStackArray: TYPE = RECORD[stack: SEQUENCE length: NAT OF PatternPC];

PatternOpCodeArray: TYPE = RECORD[opCodes: SEQUENCE length: NAT OF OpCode];

PatternDataArray: TYPE = RECORD[opCodes: SEQUENCE length: NAT OF NAT];

PatternNextArray: TYPE = RECORD[opCodes: SEQUENCE length: NAT OF PatternPC];

PatternLooksArray: TYPE = RECORD[looks: SEQUENCE length: NAT OF TextLooks.Looks];

ClassArray: TYPE = RECORD[classes: SEQUENCE length: NAT OF CharClass];

ReturnCodeArray: TYPE = RECORD[returnCodes: SEQUENCE length: NAT OF ReturnCode];

NameArray: TYPE = RECORD [array: SEQUENCE length: NAT OF NameRec];

NameRec: TYPE = RECORD [name: ROPE, at, atEnd: Offset, looks: TextLooks.Looks];

CodeContent: TYPE = RECORD[

opCodes: REF PatternOpCodeArray,

looks: REF PatternLooksArray,

data: REF PatternDataArray,

next: REF PatternNextArray

];

Code: TYPE = REF CodeContent;

StackContent: TYPE = RECORD[

pos: Index,

pc: REF PatternStackArray,

nextPos: REF TextStackArray,

returnCode: REF ReturnCodeArray

];

Stack: TYPE = REF StackContent;

FinderRecord: TYPE = RECORD [

stack: Stack,

forwardProgram: Code,

backwardProgram: Code,

classes: REF ClassArray,

nameArray: REF NameArray,

ropeReader: RopeReader.Ref,

lksReader: LooksReader.Ref,

runReader: RunReader.Ref,

wordSearch: BOOL ← FALSE

];

Finder: TYPE = REF FinderRecord;