Regular Expression implementation

• The Matchpack
• The Patternpack
  
• Functions of package JesTool
• Node or type RE_ELEM
  

More specifics about the implementation, grouping and capturing.
The Regular expression implementation uses packages

with Y2018.Text.Jets; use Y2018.Text.Jets; -- contain I_A and I_A_Array
with Y2018.Text.Jets.MatchPack;
with Y2018.Text.Jets.PatternPack;

p: PatternPack.Pattern_AC:=new PatternPack.Pattern
startPos:Integer:=1
nextPos: Integer
m: MatchPack.Match_TY

1. To start the process we have to create the pattern by calling: PatternPack.compileM(p,"^.*?(P[\w]*).*"c).
2. Match the source string to the pattern. If pattern is found the function retrurns TRUE else FALSE: PatternPack.matches(p,startPos,nextPos,"Please Y"c,m).
3. If success then we have to retreive the result to a I_A_Array by the call r:I_A_ARRAY:=MatchPack.getMatch(m). I_A_ARRAY is a two dimensional array of Integers pairs (I_A type). In a I_A variable first index is the start point where we found the value we searched for and the second index is the end point of the same searched
4. In our case we get two I_A values, one for the whole source string and one for the value "Please", without the " Y" part. In I_A_Array index 0 contain the whole string and index 1 the "Please". But we got only index values not these strings
5. To access strings we use subIA-function. subIA("Please Y"c,r(0)) return the string "Please Y"c, and subIA("Please Y"c,r(1)) returns "Please"c