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

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"
@@ -305,18 +305,41 @@ 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--;
 
+		for (x=1; x<=3; x++) /* Three chances to guess that word... */
+		{
+				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++)
 				{
@@ -352,6 +375,9 @@ helpSQL(const char *topic, unsigned short int pager)
 										break;
 						}
 				}
+				if (help_found) /* Don't keep trying if we got a match */
+						break;
+		}
 
 		if (!help_found)
 			fprintf(output, _("No help available for \"%-.*s\".\nTry \\h with no arguments to see available help.\n"), (int) len, topic);