How to use the Coco/R for F#
============================

First, if you have already used the version of Coco/R for C#, you'll see that this version is very similar.

Differences to Coco/R for C#
============================
•	The grammar has been extended to allow the usage of variables.
•	The comment syntax has been adapted to “//” for line comments, and “(*” to “*)” for nested block comments, like in F#.

The structure for a Coco/R grammar for F# is as follows
=======================================================

Coco=
	[Imports]
	"COMPILER" ident
	[Declarations]
	[
		"VARIABLES" AnyVariables
		"INITVARIABLES" AnyVariablesDeclaration
	]
	ScannerSpecification
	ParserSpecification
	"END" ident ’.’
.

The imports section can be used to call libraries, e.g.: “open System.IO”.

The declarations section may be used to declare global methods of the class Parser, e.g.:
	member x.Print = printf “Value %d” t.value;

Use the variables section to declare member variables for the parser class, e.g.: 
	val a : int
	val d : string

Initialize the variables declared in the variables section in the initvariables section. This will be copied into the constructor of the parser class, e.g.:
	a = 0;
	b= "";



How to use output attributes?
=============================
Input and output attributes can be declared like input and output parameters in F#.

Example:

<(atrib : int), (rr : string byref)>

atrib represents an input attribute of type int, rr represents an output attribute of the type string.


Usage of output attributes:

To use an output attribute, it is necessary to declare a variable (in the following example: z) in the “caller”:

S = (. z = ref 0 in .)
    Number<z> (. printf "The out value is %d" !z; .)
.


And to fill it by the “Callee”:

Number <value : int byref> =
	number (. value <- Convert.ToInt32(x.t.value); .) .



General:
========

The use of the scanner and parser generated by the F# version of Coco/R is the same as of the other versions of Coco/R, thus it’s highly recommended to read the documentation available at
http://www.ssw.uni-linz.ac.at/coco/.