Support trailing semicolon in gp_read_str_multiline()

[Jeroen Demeyer <jdemeyer@cage.ugent.be>]

Dear pari-dev,

Attached patch changes gp_read_str_multiline() to look at trailing a 
semicolon. If there is, the output is silenced (i.e. gnil is returned).

In other words, gp_read_str_multiline("a = 1") will return a t_INT 1 
while gp_read_str_multiline("a = 1;") will return gnil.


Cheers,
Jeroen.

commit fa8256f515c94b953430bf2944a10bf62f312151
Author: Jeroen Demeyer <jdemeyer@cage.ugent.be>
Date:   Tue Jan 12 15:30:48 2016 +0100

    Support final semicolon to silence output in gp_read_str_multiline()

diff --git a/src/language/es.c b/src/language/es.c
index 3c7a5e9..2e56178 100644
--- a/src/language/es.c
+++ b/src/language/es.c
@@ -214,6 +214,10 @@ init_filtre(filtre_t *F, Buffer *buf)
 /**                        INPUT METHODS                           **/
 /**                                                                **/
 /********************************************************************/
+
+static int
+is_silent(char *s) {return s[strlen(s) - 1] == ';';}
+
 /* create */
 Buffer *
 new_buffer(void)
@@ -261,17 +265,28 @@ gp_read_stream(FILE *fi)
   delete_buffer(b); return x;
 }
 
+/* flags for gp_read_from_input */
+#define READ_LOOP           1
+#define READ_ALWAYS_RETURN  2
+
 static GEN
-gp_read_from_input(input_method* IM, int loop)
+gp_read_from_input(input_method* IM, unsigned int flags)
 {
   Buffer *b = new_buffer();
   GEN x = gnil;
   filtre_t F;
   do {
+    char *s;
     init_filtre(&F, b);
     if (!input_loop(&F, IM)) break;
-    if (*(b->buf)) x = readseq(b->buf);
-  } while (loop);
+    s = b->buf;
+    if (s[0])
+    {
+      x = readseq(s);
+      if ((flags & READ_ALWAYS_RETURN) == 0 && x != gnil && is_silent(s))
+        x = gnil;
+    }
+  } while (flags & READ_LOOP);
   delete_buffer(b);
   return x;
 }
@@ -330,7 +345,7 @@ gp_read_str_multiline(const char *s)
   IM.getline = &file_input;
   IM.free = 0;
 
-  return gp_read_from_input(&IM, 1);
+  return gp_read_from_input(&IM, READ_LOOP);
 }
 
 GEN