ecSyntGramma

Grammar rules allows testing complex sequences of tokens. 

Grammar is defined in Gramma property. Grammar rules are separated by the semicolon. 

Syntax of grammar definitions:

Rule ::= RuleName '=' Branch_list ';'

Branch_list ::= Item_list
              | Branch_list '|' Item_list

Item_list ::= Element
            | Item_list Element

Element ::= Item
          | Item '*'
          | Item '+'
          | Item '?'

Item ::= RuleName
       | '"' Term '"'
       | ''' Term '''
       | '<' TokenType '>'
       | '(' Item_list ')'

where: 

"Term" - case insensitive terminal, 

'Term' - case sensitive terminal, 

TokenType - name of token type, 

RuleName - name of grammar rule. 

Repeaters: 

'*' - any number of entries including none 

'+' - at least one entry 

'?' - one entry or none 

There are special grammar rule "Skip". It is used after each match operation to skip unused tokens (for example, comments). 

There is reserved rule name "Skip", that is used to specify skipping sequence. This rule is executed after each item processing. 

For example, see Pascal lexer in default lexer library, rules "class declaration", "Empty class", "Interface declaration".

Classes