charParser {qmrparser} | R Documentation |
Specific single character token.
Description
Recognises a specific single character.
Usage
charParser(char,
action = function(s) list(type="char",value=s),
error = function(p) list(type="char",pos =p))
Arguments
char |
character to be recognised |
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 |
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
orerror
function output, depending on the casestream
With information about the input, after success or failure in recognition
See Also
Examples
# fail
stream <- streamParserFromString("H")
( charParser("a")(stream) )[c("status","node")]
# ok
stream <- streamParserFromString("a")
( charParser("a")(stream) )[c("status","node")]
# ok
( charParser("\U00B6")(streamParserFromString("\U00B6")) )[c("status","node")]