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current_macro(?TermClass, ?TransPred, ?Options, ?Module)
Succeeds if TermClass is a macro with the transformation predicate
TransPred defined in module Module and flags Options.
- ?TermClass
- Term in the form Atom/Integer or atom or variable.
- ?TransPred
- Term in the form Atom/Integer or variable.
- ?Options
- List or a variable.
- ?Module
- Atom or variable.
Description
This predicate enumerates all visible macros and retrieves their
definition. The arguments TransPred and Options correspond to the
arguments of macro/3 or portray/3. Module is the definition module of
TransPred and it can be used for calling the TransPred explicitly (e.g.
using :/2).
Fail Conditions
Fails if no macro matches the input arguments.
Resatisfiable
Yes.
Exceptions
- (5) type error
- TermClass not of form Atom/Integer.
- (5) type error
- TransPred not of form Atom/Integer.
- (5) type error
- Options not a list.
Examples
[eclipse]: [user]. % define a macro
tr_a(a(X), b(X,X)).
:- local macro(a/1, tr_a/2, []).
yes.
[eclipse]: current_macro(F, T, O, M). % list visible macros
F = (-->) / 2 % predefined macro
T = trdcg / 3
O = [global, clause]
M = macro More? (;)
F = (if) / 2 % predefined macro
T = tr_if / 2
O = [global, clause]
M = coroutine More? (;)
F = a / 1 % our user defined macro
T = tr_a / 2
O = [local]
M = eclipse More? (;)
F = no_macro_expansion / 1 % predefined macro
T = trprotect / 2
O = [global, protect_arg]
M = macro More? (;)
no (more) solution.
See Also
macro / 3, portray / 3, erase_macro / 2