IISPLParserGenerator V6.0

Summary of Lex language

• Alphabet : 99 letters  : \n \t \r \x20( )-\x7F(~)            
• Operators  \ " . ^ $ [ ] - * + | ? { } ( ) / ' ,
           example [0-9a-zA-Z] [0-9]+ [a-z]*([a-z]|[0-9])*
           example  (\+|\-)?[0-9]+(\.[0-9]+)?(E(\+|\-)[0-9]+)?
• c  the non-operator character
• a : {a}
• '  numerical character
• '\x31'  '\x41' '\xa' 
• \c,[c],'c' character c literally
• \a 'a' [a]
• "s" string s literally
• "*" : {*},   "+=" : {+=}
• .   any any single character but new line[\n\r]
• a.c   : {aac,abc,acc,adc, ... }
  [a.c] : {a,.,c}
   .at   : {hat, cat, bat ... }
• [s] a character set, any one of the characters in string s
•  [abc] : {a,b,c}
   [a-z] : {a,b,c,d,e,..., z}
   [abcx-z] : {a,b,c,x,y,z}  = [a-cz-z]
   [".$[*+|?{}()/'\^\-\]] :{",.,$,[,*,+,|,?,{,},(,),/,',^,-,],} 
            but   [\\], [\], [-], [^] are not allowed
   [hc]at : {hat,cat}
• In this character set, only three characters -,^,] are treated as operator so  they must be writen with escape character such as \^,\^,\]
• [^s] any one character not in string s. same as the complement of the character set L(s), that is Alphabet-L(s)
• if Alphabet is [A-Za-z], then
      [^ABC] : {D,E,,...Z,a,b,...z}
• [^a-z] : {A,B,.., Z}
• [^hc]at : all strings of .at other than {hat,cat}  : L(.at) - {hat,cat}
• ^   a starting position of any line or string
• ^[hc]at  : {hat,cat}, but only at the begining of the string or line
• $   the ending position of the string or the position just before a string-ending newline. 
• In line based tools, it matches the ending position of any line.
   [hc]at$  : {hat,cat}, but only at the end of the string or line : {hat\n,cat\n}
• r*  zero or more strings maching r
• a* : { ,a,aa,aaa, ... }
• r+  one or more strings maching r
• a+ : {a,aa,aaa, ... }
• r?  zero or one r
• a? : { , a}
• r{m,n} : between m and n occurrences of r
• a[1,5] : {a,aa,aaa,aaaa,aaaaa}
• rs  an r followed s
• ab : {ab}
• r|s  an r or an s
• a|b : {a,b}
• (r) same as r
• (a|b) : {a,b}
• r/s r when wollowed by s
• abc/123  : { abc}  flowed by 123
• // line comment
• // cny characters to \n
• %{  anycharacters %} multiple line comment
• %{
           multiple line comments
           this is copied on to the target program
           any string “%}“ is not allowed
  %}

Lexical Analyzer generator

• %{
            comment lines
           any character strings without “%}“
  %}
  // comment
  def1 re
  def2 re
  %%
  //comment
  re     { yyoval=bexbuf; return("ID"); }
  .|[\n\r]   { return("WS"); }
  %%
  aux procedures
  ...