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more elegant solution for parsing numeric arguments, using a DCG

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This commit is contained in:
Markus Triska
2021-11-16 18:25:35 +01:00
parent 23df16ecf9
commit bd75e9c184
1 changed files with 11 additions and 13 deletions
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24
src/lib/format.pl
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@@ -328,30 +328,28 @@ cell(From, To, Es0) -->
[cell(From,To,Es)]
).
%?- numeric_argument("2f", Num, ['f'|Fs], Args0, Args).
%?- format:numeric_argument("2f", Num, ['f'|Fs], Args0, Args).
%?- numeric_argument("100b", Num, Rs, Args0, Args).
%?- format:numeric_argument("100b", Num, Rs, Args0, Args).
numeric_argument(Ds, Num, Rest, Args0, Args) :-
( Ds = [*|Rest] ->
Args0 = [Num|Args]
; numeric_argument_(Ds, [], Ns, Rest),
foldl(pow10, Ns, 0-0, Num-_),
; phrase(numeric_argument_(Ds, Rest), Ns),
foldl(plus_times10, Ns, 0, Num),
Args0 = Args
).
numeric_argument_([D|Ds], Ns0, Ns, Rest) :-
( member(D, "0123456789") ->
number_chars(N, [D]),
numeric_argument_(Ds, [N|Ns0], Ns, Rest)
; Ns = Ns0,
Rest = [D|Ds]
numeric_argument_([D|Ds], Rest) -->
( { member(D, "0123456789") } ->
{ number_chars(N, [D]) },
[N],
numeric_argument_(Ds, Rest)
; { Rest = [D|Ds] }
).
pow10(D, N0-Pow0, N-Pow) :-
N is N0 + D*10^Pow0,
Pow is Pow0 + 1.
plus_times10(D, N0, N) :- N is D + N0*10.
radix_error(lowercase, R) --> format_("~~~dr", [R]).
radix_error(uppercase, R) --> format_("~~~dR", [R]).