From: Markus Triska <triska@metalevel.at>
Date: Sun, 7 Jun 2020 21:14:23 +0000 (+0200)
Subject: ENHANCED: format_//2 now evaluates arithmetic expressions for ~d, ~D, ~f, ~r and ~R
X-Git-Tag: v0.8.127~52^2~1
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=9bb851d437f6eb49dbf2f4c47b5a9ee392dd8b21;p=scryer-prolog.git

ENHANCED: format_//2 now evaluates arithmetic expressions for ~d, ~D, ~f, ~r and ~R

Example:

    ?- phrase(format_("~d", [1+2]), Cs).
       Cs = "3"
    ;  false.
---

diff --git a/src/prolog/lib/format.pl b/src/prolog/lib/format.pl
index 8b090cf6..d91fdc91 100644
--- a/src/prolog/lib/format.pl
+++ b/src/prolog/lib/format.pl
@@ -174,7 +174,7 @@ cells([~,a|Fs], [Arg|Args], Tab, Es) --> !,
 cells([~|Fs0], Args0, Tab, Es) -->
         { numeric_argument(Fs0, Num, [d|Fs], Args0, [Arg|Args]) },
         !,
-        { number_chars(Arg, Cs0) },
+        { format_number_chars(Arg, Cs0) },
         (   { Num =:= 0 } -> { Cs = Cs0 }
         ;   { length(Cs0, L),
               (   L =< Num ->
@@ -216,12 +216,12 @@ cells([~|Fs0], Args0, Tab, Es) -->
 cells([~,s|Fs], [Arg|Args], Tab, Es) --> !,
         cells(Fs, Args, Tab, [chars(Arg)|Es]).
 cells([~,f|Fs], [Arg|Args], Tab, Es) --> !,
-        { number_chars(Arg, Chars) },
+        { format_number_chars(Arg, Chars) },
         cells(Fs, Args, Tab, [chars(Chars)|Es]).
 cells([~|Fs0], Args0, Tab, Es) -->
         { numeric_argument(Fs0, Num, [f|Fs], Args0, [Arg|Args]) },
         !,
-        { number_chars(Arg, Cs0),
+        { format_number_chars(Arg, Cs0),
           phrase(upto_what(Bs, .), Cs0, Cs),
           (   Num =:= 0 -> Chars = Bs
           ;   (   Cs = ['.'|Rest] ->
@@ -279,6 +279,10 @@ cells(Fs0, Args, Tab, Es) -->
           Fs1 = [_|_] },
         cells(Fs, Args, Tab, [chars(Fs1)|Es]).
 
+format_number_chars(N0, Chars) :-
+        N is N0, % evaluate compound expression
+        number_chars(N, Chars).
+
 n_newlines(0) --> !.
 n_newlines(N0) --> { N0 > 0, N is N0 - 1 }, [newline], n_newlines(N).
 
@@ -327,7 +331,8 @@ pow10(D, N0-Pow0, N-Pow) :-
         N is N0 + D*10^Pow0,
         Pow is Pow0 + 1.
 
-integer_to_radix(I, R, Which, Cs) :-
+integer_to_radix(I0, R, Which, Cs) :-
+        I is I0, % evaluate compound expression
         must_be(integer, I),
         must_be(integer, R),
         (   \+ between(2, 36, R) ->