[Pharo-project] Issue 3547 in pharo: Have a look at the new match: implementation
Status: Accepted Owner: stephane...@gmail.com Labels: Milestone-1.3 New issue 3547 by stephane...@gmail.com: Have a look at the new match: implementation http://code.google.com/p/pharo/issues/detail?id=3547 Collections-ul.420 Hi Squeakers, Latest trunk version broke the Aida/web and Herbert managed to find the reason in new behavior of String>>match: which doesn't allow two '**' in pattern anymore. In Aida the matching patterns are usually composed out of many strings and as it happens two stars occurs in Aida's default installation already. Because this new match behavior (not allowing two '**') is new only in Squeak but allowed in all other Smalltalks, I propose to reconsider this decision and better retract back to old behavior. answer: ------ The old behavior was definitely wrong. Here are two examples with the old behavior from the corresponding issue (http://bugs.squeak.org/view.php?id=6841 ): '*#' match: 'e'. "false" '**' match: 'e'. "false" If you look at the previous version of the method from 2004 (I don't know if this is the original or not), then you'll see that it tried to raise an error if the string contained '**', but it failed to do so because of this bug. So the intended behavior - to disallow ** in the pattern - is not new at all. IMHO the best solution to this problem is to rewrite the method to allow any combination of * and # in the pattern.
Comment #1 on issue 3547 by stephane...@gmail.com: Have a look at the new match: implementation http://code.google.com/p/pharo/issues/detail?id=3547 A new version of Collections was added to project The Inbox: http://source.squeak.org/inbox/Collections-ul.420.mcz ==================== Summary ==================== Name: Collections-ul.420 Author: ul Time: 15 January 2011, 1:57:14.662 pm UUID: aadc4c69-dd68-4f46-8370-dda4404f0153 Ancestors: Collections-mtf.419 - do not raise an error in String >> #match: if the receiver contains '**' or '*#' as a substring. - fixed the comment in String >> #match: =============== Diff against Collections-mtf.419 =============== Item was changed: ----- Method: String>>match: (in category 'comparing') ----- match: text "Answer whether text matches the pattern in this string. Matching ignores upper/lower case differences. Where this string contains #, text may contain any character. Where this string contains *, text may contain any sequence of characters." ^ self startingAt: 1 match: text startingAt: 1 " '*' match: 'zort' true '*baz' match: 'mobaz' true '*baz' match: 'mobazo' false '*baz*' match: 'mobazo' true '*baz*' match: 'mozo' false 'foo*' match: 'foozo' true 'foo*' match: 'bozo' false 'foo*baz' match: 'foo23baz' true 'foo*baz' match: 'foobaz' true 'foo*baz' match: 'foo23bazo' false 'foo' match: 'Foo' true 'foo*baz*zort' match: 'foobazort' false + 'foo*baz*zort' match: 'foobazzort' true - 'foo*baz*zort' match: 'foobazzort' false '*foo#zort' match: 'afoo3zortthenfoo3zort' true '*foo*zort' match: 'afoodezortorfoo3zort' true "! Item was changed: ----- Method: String>>startingAt:match:startingAt: (in category 'comparing') ----- startingAt: keyStart match: text startingAt: textStart "Answer whether text matches the pattern in this string. Matching ignores upper/lower case differences. Where this string contains #, text may contain any character. Where this string contains *, text may contain any sequence of characters." + | anyMatch matchStart matchEnd i matchStr j ii jj | i := keyStart. j := textStart. + + "Process consecutive *s and #s at the beginning." + anyMatch := false. + [ i <= self size and: [ + (self at: i) + caseOf: { + [ $* ] -> [ + anyMatch := true. + i := i + 1. + true ]. + [ $# ] -> [ + i := i + 1. + j := j + 1. + true ] } + otherwise: [ false ] ] ] whileTrue. + i > self size ifTrue: [ + ^j - 1 = text size or: [ "We reached the end by matching the character with a #." + anyMatch and: [ j <= text size ] "Or there was a * before the end." ] ]. + matchStart := i. - "Check for any #'s" - [i > self size ifTrue: [^ j > text size "Empty key matches only empty string"]. - (self at: i) = $#] whileTrue: - ["# consumes one char of key and one char of text" - j > text size ifTrue: [^ false "no more text"]. - i := i+1. j := j+1]. - - "Then check for *" - (self at: i) = $* - ifTrue: [i = self size ifTrue: - [^ true "Terminal * matches all"]. - "* means next match string can occur anywhere" - anyMatch := true. - matchStart := i + 1] - ifFalse: ["Otherwise match string must occur immediately" - anyMatch := false. - matchStart := i]. - "Now determine the match string" matchEnd := self size. + (ii := self indexOf: $* startingAt: matchStart) > 0 ifTrue: [ matchEnd := ii-1 ]. + (ii := self indexOf: $# startingAt: matchStart) > 0 ifTrue: [ matchEnd := matchEnd min: ii-1 ]. - (ii := self indexOf: $* startingAt: matchStart) > 0 ifTrue: - [ii = matchStart ifTrue: [self error: '** not valid -- use * instead']. - matchEnd := ii-1]. - (ii := self indexOf: $# startingAt: matchStart) > 0 ifTrue: - [ii = matchStart ifTrue: [self error: '*# not valid -- use #* instead']. - matchEnd := matchEnd min: ii-1]. matchStr := self copyFrom: matchStart to: matchEnd. "Now look for the match string" [jj := text findString: matchStr startingAt: j caseSensitive: false. anyMatch ifTrue: [jj > 0] ifFalse: [jj = j]] whileTrue: ["Found matchStr at jj. See if the rest matches..." (self startingAt: matchEnd+1 match: text startingAt: jj + matchStr size) ifTrue: [^ true "the rest matches -- success"]. "The rest did not match." anyMatch ifFalse: [^ false]. "Preceded by * -- try for a later match" j := j+1]. ^ false "Failed to find the match string"!
Updates: Labels: Type-Squeak Difficulty-Easy Comment #2 on issue 3547 by stephane...@gmail.com: Have a look at the new match: implementation http://code.google.com/p/pharo/issues/detail?id=3547 (No comment was entered for this change.)
Comment #3 on issue 3547 by stephane...@gmail.com: Have a look at the new match: implementation http://code.google.com/p/pharo/issues/detail?id=3547 ame: CollectionsTests-ul.179 Author: ul Time: 15 January 2011, 1:58:09.591 pm UUID: eda65a29-e17b-634b-b99c-e6f862302701 Ancestors: CollectionsTests-nice.178 - updated StringTest >> #testMatch to reflect the changes of Collections-ul.420 =============== Diff against CollectionsTests-nice.178 =============== Item was changed: ----- Method: StringTest>>testMatch (in category 'test-comparing') ----- testMatch + #('**' 'f**' 'f**o' 'f*' '*f*' 'f#*' 'f##' '*oo' '#oo' '*o*' '#o#' '#o*' '*o#' 'fo*' 'fo#' '*foo*' '###' '*#' 'f*#' 'f*#o') - #('**' '*#' 'f**' 'f*#' 'f**o' 'f*#o') do: [ :each | - self should: [ each match: 'foo' ] raise: Error ]. - #('f*' '*f*' 'f#*' 'f##' '*oo' '#oo' '*o*' '#o#' '#o*' '*o#' 'fo*' 'fo#' '*foo*' '###') do: [ :each | self assert: (each match: 'foo') ]. #('bar' 'foo#' '#foo' '*foo#' '#foo*' '*bar*') do: [ :each | self deny: (each match: 'foo') ]!
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