Attached is a patch that enhances the "\h" capability in psql. I often

find myself typing a command and then wanting to get the syntax for it.
So I do a ctrl-a and add a \h: but psql does not recognize the command,
because I have stuff attached to it (e.g. "alter table foobar"), so I
have to scroll over and delete everything except the name of the command
itself. This patch gives \h three chances to match: if nothing matches
the complete string (current behavior), it tries to match the first two
words (e.g. "ALTER TABLE"). If that fails, it tries to match the first
word (e.g. "DELETE").

Greg Sabino Mullane

diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9c1e6d3a57459f8c9652befb70c42fbfcc54562e..1bbe4acc43fa7a3f8d677c7fa676f87daa468a44 100644 (file)
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2005, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/help.c,v 1.102 2005/06/14 02:57:41 momjian Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/help.c,v 1.103 2005/07/06 03:14:48 momjian Exp $
  */
 #include "postgres_fe.h"
 #include "common.h"
@@ -305,52 +305,78 @@ helpSQL(const char *topic, unsigned short int pager)
        }
        else
        {
-               int                     i;
+                       int                     i,j,x=0;
                bool            help_found = false;
                FILE       *output;
-               size_t          len;
+               size_t          len, wordlen;
                int                     nl_count = 0;
                char       *ch;
 
-               /* don't care about trailing spaces or semicolons */
+               /* User gets two chances: exact match, then the first word */
+               
+               /* First pass : strip trailing spaces and semicolons */
                len = strlen(topic);
                while (topic[len - 1] == ' ' || topic[len - 1] == ';')
-                       len--;
-
-               /* Count newlines for pager */
-               for (i = 0; QL_HELP[i].cmd; i++)
-               {
-                       if (pg_strncasecmp(topic, QL_HELP[i].cmd, len) == 0 ||
-                               strcmp(topic, "*") == 0)
-                       {
-                               nl_count += 5;
-                               for (ch = QL_HELP[i].syntax; *ch != '\0'; ch++)
-                                       if (*ch == '\n')
-                                               nl_count++;
-                               /* If we have an exact match, exit.  Fixes \h SELECT */
-                               if (pg_strcasecmp(topic, QL_HELP[i].cmd) == 0)
-                                       break;
-                       }
-               }
-
-               output = PageOutput(nl_count, pager);
+                               len--;
 
-               for (i = 0; QL_HELP[i].cmd; i++)
+               for (x=1; x<=3; x++) /* Three chances to guess that word... */
                {
-                       if (pg_strncasecmp(topic, QL_HELP[i].cmd, len) == 0 ||
-                               strcmp(topic, "*") == 0)
-                       {
-                               help_found = true;
-                               fprintf(output, _("Command:     %s\n"
-                                                                 "Description: %s\n"
-                                                                 "Syntax:\n%s\n\n"),
-                                               QL_HELP[i].cmd,
-                                               _(QL_HELP[i].help),
-                                               _(QL_HELP[i].syntax));
-                               /* If we have an exact match, exit.  Fixes \h SELECT */
-                               if (pg_strcasecmp(topic, QL_HELP[i].cmd) == 0)
-                                       break;
-                       }
+                               if (x>1) /* Nothing on first pass - try the opening words */
+                               {
+                                               wordlen=j=1;
+                                               while (topic[j] != ' ' && j++<len)
+                                                               wordlen++;
+                                               if (x==2)
+                                               {
+                                                               j++;
+                                                               while (topic[j] != ' ' && j++<=len)
+                                                                               wordlen++;
+                                               }
+                                               if (wordlen >= len) /* Don't try again if the same word */
+                                               {
+                                                               output = PageOutput(nl_count, pager);
+                                                               break;
+                                               }
+                                               len = wordlen;
+                               }
+
+                               /* Count newlines for pager */
+                               for (i = 0; QL_HELP[i].cmd; i++)
+                               {
+                                               if (pg_strncasecmp(topic, QL_HELP[i].cmd, len) == 0 ||
+                                                               strcmp(topic, "*") == 0)
+                                               {
+                                                               nl_count += 5;
+                                                               for (ch = QL_HELP[i].syntax; *ch != '\0'; ch++)
+                                                                               if (*ch == '\n')
+                                                                                               nl_count++;
+                                                               /* If we have an exact match, exit.  Fixes \h SELECT */
+                                                               if (pg_strcasecmp(topic, QL_HELP[i].cmd) == 0)
+                                                                               break;
+                                               }
+                               }
+                               
+                               output = PageOutput(nl_count, pager);
+                               
+                               for (i = 0; QL_HELP[i].cmd; i++)
+                               {
+                                               if (pg_strncasecmp(topic, QL_HELP[i].cmd, len) == 0 ||
+                                                               strcmp(topic, "*") == 0)
+                                               {
+                                                               help_found = true;
+                                                               fprintf(output, _("Command:     %s\n"
+                                                                                                                                       "Description: %s\n"
+                                                                                                                                       "Syntax:\n%s\n\n"),
+                                                                                               QL_HELP[i].cmd,
+                                                                                               _(QL_HELP[i].help),
+                                                                                               _(QL_HELP[i].syntax));
+                                                               /* If we have an exact match, exit.  Fixes \h SELECT */
+                                                               if (pg_strcasecmp(topic, QL_HELP[i].cmd) == 0)
+                                                                               break;
+                                               }
+                               }
+                               if (help_found) /* Don't keep trying if we got a match */
+                                               break;
                }
 
                if (!help_found)