(!******************************************************
   Mosel User Guide Example Problems
   ================================= 

   file regex.mos 
   ``````````````
   Regular expression matching and replacement.
 
   (c) 2015 Fair Isaac Corporation
       author: S. Heipcke, Apr 2015
*******************************************************!)
model "test regex" 
 uses "mmsystem"

 declarations
  m: array(0..3) of textarea  
        ! m(0) whole identified zone,  m(1) [,...,m(9)] match results
  t: text
 end-declarations

!**** Pattern matching ****
 t:="MyValue=10,Sometext mytext MoretextMytext2, MYVAL=1.5 mYtext3"
! Display all strings starting with 'My' (case insensitive)
 m(0).succ:=1
 while (regmatch(t, '\<My\(\w*\)', m(0).succ, REG_ICASE, m))
  writeln("Word starting with 'My': ", 
   copytext(t,m(0)), " (", copytext(t,m(1)),")")

! Display all strings containing 'My' not at beginning (case insensitive)
 m(0).succ:=1
 while (regmatch(t, '\w+((My)(\w*))', m(0).succ, REG_ICASE+REG_EXTENDED, m))
  writeln("String containing 'My' (not at beginning): ", 
   copytext(t,m(0)), " (", copytext(t,m(1)), "=", copytext(t,m(2)) ,
   "+", copytext(t,m(3)), ")")

! Alternative way of stating the same expression
 m(0).succ:=1
 while (regmatch(t, '[[:alnum:]_]+((My)([[:alnum:]_]*))', m(0).succ,  
        REG_ICASE+REG_EXTENDED, m))
  writeln("String containing 'My' (not at beginning): ", 
   copytext(t,m(0)), " (", copytext(t,m(1)), "=", copytext(t,m(2)) ,
   "+", copytext(t,m(3)), ")")
 
(!
 < beginning of word
 w or [:alnum:]_  alphanumeric or underscore characters
 * 0 or more times
 () select the result to be returned as the match, mask with backslash in BRE
 + 1 or more times (only in ERE) 
!)


!**** Replacement of matching expressions ****
! Replace a dates of the format yyyy-mm-dd to the format dd/mm/yyyy
 t:="date1=20/11/2010,date2=1-Oct-2013,date3=2014-6-30"
 numr:= regreplace(t, '([[:digit:]]{4})-([01]?[[:digit:]])-([0-3]?[[:digit:]])',
              '\3/\2/\1', 1, REG_EXTENDED) 
 if numr>0 then
  writeln(numr, " replacements: ", t)
 end-if 

! The same using BRE syntax:
 t:="date1=20/11/2010,date2=1-Oct-2013,date3=2014-6-30"
 writeln( regreplace(t, '\(\d\{4\}\)-\([01]\{0,1\}\d\)-\([0-3]\{0,1\}\d\)',
         '\3/\2/\1' ),  " replacements: ", t)
! The same more readable (ERE syntax):
 numr:= regreplace(t, '(\d{4})-([01]{0,1}\d)-([0-3]{0,1}\d)',
         '\3/\2/\1', 1, REG_EXTENDED ) 

(!
 \d or [:digit:]  numerical character
 ?  0 times or once (ERE only)
 {M,N}  minimum M and maximum N match count
 []  set of possible character matches
!) 

end-model