File: API.txt

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tcl-sugar 0.1-1
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--------------------------------------------------------------------------------
GENERAL INFORMATION
--------------------------------------------------------------------------------

To require the sugar package, use:

	package require sugar

--------------------------------------------------------------------------------
SUGAR MACRO API
--------------------------------------------------------------------------------

sugar::proc name args body
	Creates a Tcl procedure exactly like [proc] does, but
	performs macro expansion in the body of the procedure
	just before to create it.

sugar::macro name arglist body
	Define a command macro with the specified name. The macro body is
	called for every "macro usage", with the arguments of the usage.
	The macro must return a Tcl list with every element representing
	an argument of the code to expand in place of the macro usage.

	Example:

	sugar::macro first {macroname list} {
		list lindex $list 0
	}

	The macro can have more than a name, like in the following
	example:

	sugar::macro {first second third} {macroname list} {
		set idx [lsearch -exact {first second third} $macroname]
		list lindex $list $idx
	}

sugar::syntaxmacro name arglist body
	Define a syntax macro: a macro that is called regardless of
	it's name for every command in a procedure defined with sugar::proc.
	Syntax macros works like command macros defined with sugar::macro.

	For syntax macros, the arglist argument is often "args" because
	a syntax macro can't know the number of agruments in input
	in advance (being called for every command in the script).

sugar::transformermacro name list body
	Define a transformer macro. The transformer macro is called
	for every element of the program the is belived a script (for example
	the second argument of the [while] command). The list argument
	is a Tcl list representing the script in an easy to parse form.
	Every element of the list is a list represeting a Tcl command
	of the original script.
	Every element of the command is a two-element list representing
	an element an element of the command in the original source
	code, where the first element represents the type of the token,
	and the second the actual value of the token.

	The following are the only token types defined:

	SPACE - A separator between arguments. A command may start
	        with a space due to indentation.
	TOK   - Every valid Tcl argument, including the command name.
	EOL   - A command separator argument. May be ";" or a newline, or
	        a mix between spaces, newlines, and ";".

	An example of script in list form is the following:

	{{{TOK puts} {SPACE { }} {TOK Hello} {EOL {;}}}
	 {{TOK set} {SPACE { }} {TOK x} {SPACE { }} {TOK 10} {EOL {;}}}}

	A transformer macro should return a list of the same form
	that will be converted back to a Tcl script in source form
	by token concatenation.

sugar::scriptToList script
	Lower-level API to turn a script into its list representation.

sugar::listToScript list
	Lower-level API to turn a list representing a script into a
	script.

sugar::expandScriptToken script
	Expand macros in the Tcl script 'script', and return it.
	Useful to write macros for commands with script as arguments,
	in order to perform macro expansion for they.

sugar::expandExprToken expr
	Expand macros in the [expr] expression 'expr', and return it.
	Useful to write macros for commands with [expr] expressions
	as arguments, in order to perform macro expansion for they.

sugar::currentProcName
	Return the fully-qualified name of the procedure currently
	processed by the macro system. Macros can call this function
	to know the name of the procedure in which the expansion
	is being performed. The following macro expands to a
	[put] call with the name of the procedure where it is used:

	sugar::macro PrintMyProc args {
		list puts [sugar::currentProcName]
	}

sugar::currentProcTail
	Equivalent to [namespace tail [sugar::currentProcName]]

sugar::currentProcNamespace
	Equivalent to [namespace qualifiers [sugar::currentProcName]]

sugar::uniqueName
	Return a name guaranteed to be unique for every call. It's
	used to create non-colliding variable or procedure names
	for macro expansion.

--------------------------------------------------------------------------------
READY TO USE MACROS PART OF SUGAR
--------------------------------------------------------------------------------
sugar::tailrecproc name args body
	A wrapper to [proc] that converts tail recursive calls in
	iterations. The user should not use [return] to return
	the value of the tail call (Tcl will return the value
	of the last command executed, so [return] is useless in
	such a case, and tailrecproc will not be able to perform
	the conversion). Tailcalls are detected inside [if] branches
	at any depth. Currently tail calls inside [switch] are not
	processed, so the user should write the tail-recursive procedure
	using if/elseif/else.

	An usage example is inside the exaple directory, tailcall.tcl.