ref: 463f3b41ac6a17f6fe88f6c114aa849876bfcf4e
parent: 0cf3816c9419954317fd54da5a063615402bf1d1
author: Peter Mikkelsen <peter@pmikkelsen.com>
date: Thu Jul 22 13:35:34 EDT 2021
Warn about singleton variables in clauses, as it is often a sign of a mis-spelling
--- a/loader.pl
+++ b/loader.pl
@@ -19,17 +19,18 @@
close(Stream).
read_and_handle_terms(Stream, Module0, Module) :-
- ( read_one_term(Stream, Term)
- -> handle_term(Term, Module0, Module1),
+ ( read_one_term(Stream, Term, Singles)
+ -> handle_term(Term, Singles, Module0, Module1),
read_and_handle_terms(Stream, Module1, Module)
; Module = Module0
).
-read_one_term(Stream, Term) :-
+read_one_term(Stream, Term, Singles) :-
consume_whitespace(Stream),
peek_char(Stream, NextCh),
NextCh \= end_of_file,
- read_term(Stream, Term, []).
+ read_term(Stream, Term, [singletons(Singletons)]),
+ singleton_names(Singletons, Singles).
whitespace(' '). whitespace(' ').@@ -43,20 +44,34 @@
; true
).
-handle_term(:- Directive, Module, NewModule) :-
+singleton_names([], []).
+singleton_names([Name = _|Rest0], Names) :-
+ singleton_names(Rest0, Rest),
+ ( atom_concat('_', _, Name)+ -> Names = Rest
+ ; Names = [Name|Rest]
+ ).
+
+handle_term(:- Directive, _, Module, NewModule) :-
!,
handle_directive(Directive, Module, NewModule).
-handle_term(Head :- Body, Module, Module) :-
+handle_term(Head :- Body, Singles, Module, Module) :-
!,
- Module:assertz(Head :- Body).
-handle_term(Head --> Body, Module, Module) :-
+ handle_clause(Head, Body, Singles, Module).
+handle_term(Head --> Body, Singles, Module, Module) :-
!,
write('DCG RULE: '),write(Head --> Body),
nl.
-handle_term(Head, Module, Module) :-
- Module:assertz(Head).
+handle_term(Head, Singles, Module, Module) :-
+ handle_clause(Head, true, Singles, Module).
+handle_clause(Head, Body, Singletons, Module) :-
+ functor(Head, Name, Arity),
+ PredicateIndicator = Name / Arity,
+ warn_singletons(PredicateIndicator, Singletons),
+ Module:assertz(Head :- Body).
+
handle_directive(op(Priority, Specifier, Operator), Module, Module) :-
Module:op(Priority, Specifier, Operator).
handle_directive(include(F), Module, NewModule) :-
@@ -72,6 +87,15 @@
handle_directive(D, Module, Module) :-
write('Cannot handle directive: '),write(D),
+ nl.
+
+warn_singletons(_, []).
+warn_singletons(PI, Singles) :-
+ write('Warning: singleton variables in '), + write(PI),
+ write(': '),+ write(Singles),
+ write('.'),nl.
ensure_loads(_) :- fail.