Search code examples
stringsubstringsmalltalkvisualworks

visualworks smalltalk: how can I detect substring from a string, is it possible?

as title suggests I'm not sure best route to detect the presence of a substring in a string, for example:

OverExtended:anErrorMessage

"anErrorMessage = 'error: robot arm extended too far' "

(anErrorMessage **contains:** 'extended too far')
ifTrue:[
   ...
   ...
]
ifFalse:[
   ...
   ...
].

Now I know the above doesnt work, but is there an existing method for checking for substrings??

Solution

  • I have found an answer that is both simple and accurate in all scenarios w/o dependancy on readStreams or extentions to 'naitive' VW as far back as VW7.4:

    simply use findString:startingAt: and do a greater then zero check for # of occurences

    sample:

    |string substring1 substring2|
string:= 'The Quick Brown Fox'.
substring1:= 'quick'.
substring2:='Quick'.

"below returns FALSE as 'quick' isnt found"
(string findString: substring1 startingAt:1)>0
ifTrue:[^'found [quick]'].

"below returns TRUE as 'Quick' is found"
(string findString: substring2 startingAt:1)>0
ifTrue:[^'found [Quick]'].

^'found nothing'.