November 2010 - Pharo-dev - lists.pharo.org

Re: [Pharo-project] [squeak-dev] Re: [ENH] Syntax extension for continuations

by Igor Stasenko

On 1 November 2010 05:04, Levente Uzonyi <leves(a)elte.hu> wrote: > On Mon, 1 Nov 2010, Igor Stasenko wrote: > >> Hello, >> >> Out of curiosity, i tried to look how it would be hard to change >> parser to support extended continuation syntax. >> And it was quite simple, i had to change only single method! >> >> A new syntax using double semicolon ';;' to indicate a continuation. >> >> So, code like: >> >> self foo ;; bar ;; zork >> >> is equivalent to: >> >> self foo bar zork >> >> But when its going to binary, or keyword messages, it allows to write >> more clean code, >> because it not requires using parenthesis. >> >> For instance: >> >> (1/10) asFloat >> >> with new syntax can be written as: >> >> 1/10 ;; asFloat >> >> More complex example: >> >> ((self foo: bar) + 10 ) baz >> >> can be written as >> >> self foo: bar ;; + 10 ;; baz >> >> >> Note, that it is same number of characters to type.. but is much more >> clean, and less time expensive to code, >> because when you coding, you usually type first message: >> >> self foo: bar ` >> >> and then you realising that next message is binary and hence you need >> to go back to beginning of line and put open paren there: >> >> `( self foo: bar >> >> then again, go to the end of message, and continue typing: >> >> ( self foo: bar ` ) + 10 >> >> ` - is cursor position. >> >> so, it is much more keystrokes & navigation than just typing two >> semicolons :) >> >> P.S. don't burn me for my herecy, please :) > > This idea comes up every few years. This post sums up well the last attempt: > http://blog.3plus4.org/2007/08/30/message-chains/ . > Yes. I know. > I don't think it's worth changing the syntax for this. IMHO 1-2 pairs of > parentheses usually improve readability. More parenthesis is rarely needed. > Also mixing ;; with ; makes the code harder to understand. Try this: self > foo ; bar ;; baz ; foo ;; bar ; baz. > this is incorrect syntax. > Note that the term 'continuation' means a totally different thing: > http://en.wikipedia.org/wiki/Continuation . > It was called so in tiny smalltalk (if i remember), when i first learned a syntax. You name it. > > Levente > >> >> -- >> Best regards, >> Igor Stasenko AKA sig. >> > > -- Best regards, Igor Stasenko AKA sig.

Nov. 1, 2010

Re: [Pharo-project] [ENH] Syntax extension for continuations

by Levente Uzonyi

On Mon, 1 Nov 2010, Igor Stasenko wrote: > Hello, > > Out of curiosity, i tried to look how it would be hard to change > parser to support extended continuation syntax. > And it was quite simple, i had to change only single method! > > A new syntax using double semicolon ';;' to indicate a continuation. > > So, code like: > > self foo ;; bar ;; zork > > is equivalent to: > > self foo bar zork > > But when its going to binary, or keyword messages, it allows to write > more clean code, > because it not requires using parenthesis. > > For instance: > > (1/10) asFloat > > with new syntax can be written as: > > 1/10 ;; asFloat > > More complex example: > > ((self foo: bar) + 10 ) baz > > can be written as > > self foo: bar ;; + 10 ;; baz > > > Note, that it is same number of characters to type.. but is much more > clean, and less time expensive to code, > because when you coding, you usually type first message: > > self foo: bar ` > > and then you realising that next message is binary and hence you need > to go back to beginning of line and put open paren there: > > `( self foo: bar > > then again, go to the end of message, and continue typing: > > ( self foo: bar ` ) + 10 > > ` - is cursor position. > > so, it is much more keystrokes & navigation than just typing two semicolons :) > > P.S. don't burn me for my herecy, please :) This idea comes up every few years. This post sums up well the last attempt: http://blog.3plus4.org/2007/08/30/message-chains/ . I don't think it's worth changing the syntax for this. IMHO 1-2 pairs of parentheses usually improve readability. More parenthesis is rarely needed. Also mixing ;; with ; makes the code harder to understand. Try this: self foo ; bar ;; baz ; foo ;; bar ; baz. Note that the term 'continuation' means a totally different thing: http://en.wikipedia.org/wiki/Continuation . Levente > > -- > Best regards, > Igor Stasenko AKA sig. >

Nov. 1, 2010

Re: [Pharo-project] [ENH] Syntax extension for continuations

by Igor Stasenko

Here is more examples (found by searching .sources file with 3 or more '(((' ). ContextPart>>handleSignal: (((self tempAt: 1) handles: exception) and: [self tempAt: 3]) ifFalse: [ ^ self nextHandlerContext handleSignal: exception]. self tempAt: 1 ;; handles: exception ;; and: [self tempAt: 3] ;; ifFalse: [ ^ self nextHandlerContext handleSignal: exception]. Bezier3Segment. before: bezier2SegmentCount: pixelError "Compute the number of quadratic bezier segments needed to approximate this cubic with no more than a specified error" | a | a := (start x negated @ start y negated) + (3 * via1) - (3 * via2) + (end). ^ (((a r / (20.0 * pixelError)) raisedTo: 0.333333) ceiling) max: 1. after: bezier2SegmentCount: pixelError "Compute the number of quadratic bezier segments needed to approximate this cubic with no more than a specified error" | a | a := start x negated @ start y negated ;; + (3 * via1) - (3 * via2) + end. ^ a r / (20.0 * pixelError) raisedTo: 0.333333 ;; ceiling max: 1. ZipArchive before: lastIndexOfPKSignature: aSignature in: data "Answer the last index in data where aSignature (4 bytes long) occurs, or 0 if not found" | a b c d | a := aSignature first. b := aSignature second. c := aSignature third. d := aSignature fourth. (data size - 3) to: 1 by: -1 do: [ :i | (((data at: i) = a) and: [ ((data at: i + 1) = b) and: [ ((data at: i + 2) = c) and: [ ((data at: i + 3) = d) ]]]) ifTrue: [ ^i ] ]. ^0 after: lastIndexOfPKSignature: aSignature in: data "Answer the last index in data where aSignature (4 bytes long) occurs, or 0 if not found" | a b c d | a := aSignature first. b := aSignature second. c := aSignature third. d := aSignature fourth. data size - 3 to: 1 by: -1 do: [ :i | data at: i ;; = a and: [ data at: i + 1 ;; = b and: [ data at: i + 2 ;; = c and: [ data at: i + 3 ;; = d ]]] ifTrue: [ ^i ] ]. ^0 Character before: asUppercase "If the receiver is lowercase, answer its matching uppercase Character." "A tentative implementation. Eventually this should consult the Unicode table." | v | v := self charCode. (((8r141 <= v and: [v <= 8r172]) or: [16rE0 <= v and: [v <= 16rF6]]) or: [16rF8 <= v and: [v <= 16rFE]]) ifTrue: [^ Character value: value - 8r40] ifFalse: [^ self] after: asUppercase "If the receiver is lowercase, answer its matching uppercase Character." "A tentative implementation. Eventually this should consult the Unicode table." | v | v := self charCode. 8r141 <= v and: [v <= 8r172] ;; or: [16rE0 <= v and: [v <= 16rF6]] ;; or: [16rF8 <= v and: [v <= 16rFE]] ;; ifTrue: [^ Character value: value - 8r40] ifFalse: [^ self] -- Best regards, Igor Stasenko AKA sig.

Nov. 1, 2010

[Pharo-project] [ENH] Syntax extension for continuations

by Igor Stasenko

Hello, Out of curiosity, i tried to look how it would be hard to change parser to support extended continuation syntax. And it was quite simple, i had to change only single method! A new syntax using double semicolon ';;' to indicate a continuation. So, code like: self foo ;; bar ;; zork is equivalent to: self foo bar zork But when its going to binary, or keyword messages, it allows to write more clean code, because it not requires using parenthesis. For instance: (1/10) asFloat with new syntax can be written as: 1/10 ;; asFloat More complex example: ((self foo: bar) + 10 ) baz can be written as self foo: bar ;; + 10 ;; baz Note, that it is same number of characters to type.. but is much more clean, and less time expensive to code, because when you coding, you usually type first message: self foo: bar ` and then you realising that next message is binary and hence you need to go back to beginning of line and put open paren there: `( self foo: bar then again, go to the end of message, and continue typing: ( self foo: bar ` ) + 10 ` - is cursor position. so, it is much more keystrokes & navigation than just typing two semicolons :) P.S. don't burn me for my herecy, please :) -- Best regards, Igor Stasenko AKA sig.

Nov. 1, 2010