qmrparser (version 0.1.6)

commentParser: Comment token.

Description

Recognises a comment, a piece of text delimited by two predefined tokens.

Usage

commentParser(beginComment,endComment,
          action = function(s) list(type="commentParser",value=s),
          error  = function(p) list(type="commentParser",pos  =p))

Arguments

beginComment

String indicating comment beginning

endComment

String indicating comment end

action

Function to be executed if recognition succeeds. Character stream making up the token is passed as parameter to this function

error

Function to be executed if recognition does not succeed. Position of streamParser obtained with streamParserPosition is passed as parameter to this function

Value

Anonymous function, returning a list.

function(stream) --> list(status,node,stream)

From input parameters, an anonymous function is defined. This function admits just one parameter, stream, with type streamParser, and returns a three-field list:

• status "ok" or "fail"

• node With action or error function output, depending on the case

• stream With information about the input, after success or failure in recognition

Details

Characters preceded by \ are not considered as part of beginning of comment end.

Examples

# NOT RUN {
# fail
stream  <- streamParserFromString("123")
( commentParser("(*","*)")(stream) )[c("status","node")]

# ok 
stream  <- streamParserFromString("(*123*)")
( commentParser("(*","*)")(stream) )[c("status","node")]

# }