heh.
Awesome!
Thank you.
I will test this in the coming days and understand it.
For my immediate task this would be pre-mature optimization within the larger scope of work I am still cobbling together.
I will definitelly add this to the SqueakHOWTO's later this week, possibly by tomorrow.
t
---- On Sat, 27 Nov 2021 12:50:10 -0500 Eliot Miranda eliot.miranda@gmail.com wrote ----
On Sat, Nov 27, 2021 at 9:47 AM Eliot Miranda mailto:eliot.miranda@gmail.com wrote:
On Sat, Nov 27, 2021 at 8:36 AM Thiede, Christoph mailto:Christoph.Thiede@student.hpi.uni-potsdam.de wrote:
What about
{ '{|' . '|-' . '|}' . '{{' . '}}' . '[[' . ']]' . '__' . '==' . '::' . '**' . '##' . '''' } anySatisfy: [:pattern | self match: pattern]
?
Maybe also this one if the identity of the matching pattern is of interest:
{ '{|' . '|-' . '|}' . '{{' . '}}' . '[[' . ']]' . '__' . '==' . '::' . '**' . '##' . '''' }
detect: [:pattern | self match: pattern]
ifFound: [:pattern | self inform: 'Matched pattern: ' , pattern]
ifNone: [self inform: 'no match']
Best,
Christoph
PS: Don't use #| unless you explicitly want every method to be invoked always. Use #or:... instead, this is faster.
And just as importantly, never use a brace construct when a literal array will do. { '{|' . '|-' . '|}' . '{{' . '}}' . '[[' . ']]' . '__' . '==' . '::' . '**' . '##' . '''' } is created at run-time. The equivalent #('{|' '|-' '|}' '{{' '}}' '[[' ']]' '__' '==' '::' '**' '##' '''') is created at compile-time. Inspect the method in the browser or the debugger and have a look at the bytecode.
If performancer is important you'll construct a parser of some form. For example, the simplest optimization here is to check if the first character is a candidate and then if the second character is a candidate. In a parser you'd have different code executed for each first character candidate. But the below avoids doing a match until we know both characters are in the set. I've written it as a doit bit I'm imagining Firsts and Seconds are class or instance variables (the issue here is provided the matcher is called often we want Firsts and Seconds to be computed precisely once).
| patterns first second Firsts Seconds | patterns := #('{|' '|-' '|}' '{{' '}}' '[[' ']]' '__' '==' '::' '**' '##' ''''). Firsts ifNil: [Firsts := (patterns collect: #first) as: String. Seconds := (patterns collect: #second) as: String]. self size >= 2 and: [(Firsts includes: (first := self first)) and: [(Seconds includes: (second := sef second) and: [patterns includes: (ByteString with: first with: second)]]]
Oops. I meant of course
| patterns first second Firsts Seconds | patterns := #('{|' '|-' '|}' '{{' '}}' '[[' ']]' '__' '==' '::' '**' '##' ''''). Firsts ifNil: [Firsts := ((patterns collect: #first) as: Set) as: String. Seconds := ((patterns collect: #second) as: Set) as: String]. self size >= 2 and: [(Firsts includes: (first := self first)) and: [(Seconds includes: (second := sef second)
and: [patterns includes: (ByteString with: first with: second)]]]
Von: Squeak-dev mailto:squeak-dev-bounces@lists.squeakfoundation.org im Auftrag von gettimothy via Squeak-dev mailto:squeak-dev@lists.squeakfoundation.org Gesendet: Samstag, 27. November 2021 17:30:38 An: squeak-dev Betreff: [squeak-dev] Anybody got an elegent construct for this functional monstrosity?
I have a ReadStream and I want to detect some substrings in it.
This works, but it is ugly.
((self match:'{|') |
(self match:'|-') |
(self match:'|}') |
(self match:'{{') |
(self match:'}}') |
(self match:'[[') |
(self match:']]') |
(self match:'__') |
(self match:'==') |
(self match:'::') |
(self match:'**') |
(self match:'##') |
(self match:'''') )
Is anybody aware of an elegant approach to this?
Something along the lines of
self matchAny: { '{|' . '|-' . '|}' . '{{' . '}}' . '[[' . ']]' . '__' . '==' . '::' . '**' . '##' . '''' }
thx in advance