From a93dc77b0d77e622834f524e2060d516b47bbc58 Mon Sep 17 00:00:00 2001
From: Jeremy Stanley <fungi@yuggoth.org>
Date: Mon, 13 May 2019 03:06:42 +0000
Subject: [PATCH] Show possible abbreviations in help list

When listing available commands via the help command, show which
parts of a given command word are optional to type. Also test it.
---
 mudpy/command.py        | 58 +++++++++++++++++++++++++++++++++++++------------
 mudpy/tests/selftest.py |  8 ++++---
 2 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/mudpy/command.py b/mudpy/command.py
index 5ba3d28..2b20b1a 100644
--- a/mudpy/command.py
+++ b/mudpy/command.py
@@ -195,23 +195,53 @@ def help(actor, parameters):
     # no specific command word was indicated
     else:
 
-        # give a sorted list of commands with descriptions if provided
-        output = "These are the commands available to you:$(eol)$(eol)"
-        sorted_commands = list(actor.universe.groups["command"].keys())
-        sorted_commands.sort()
-        for item in sorted_commands:
-            command = actor.universe.groups["command"][item]
+        # preamble text
+        output = ("These are the commands available to you [brackets indicate "
+                  "optional portion]:$(eol)$(eol)")
+
+        # list command names in alphabetical order
+        for command_name, command in sorted(
+                actor.universe.groups["command"].items()):
+
+            # skip over disallowed commands
             if actor.can_run(command):
-                description = command.get("description")
-                if not description:
-                    description = "(no short description provided)"
+
+                # start incrementing substrings
+                for position in range(1, len(command_name) + 1):
+
+                    # we've found our shortest possible abbreviation
+                    candidate = mudpy.misc.find_command(
+                            command_name[:position])
+                    try:
+                        if candidate.subkey == command_name:
+                            break
+                    except AttributeError:
+                        pass
+
+                # use square brackets to indicate optional part of command name
+                if position < len(command_name):
+                    abbrev = "%s[%s]" % (
+                        command_name[:position], command_name[position:])
+                else:
+                    abbrev = command_name
+
+                # supply a useful default if the short description is missing
+                description = command.get(
+                    "description", "(no short description provided)")
+
+                # administrative command names are in red, others in green
                 if command.get("administrative"):
-                    output += "   $(red)"
+                    color = "red"
                 else:
-                    output += "   $(grn)"
-                output += item + "$(nrm) - " + description + "$(eol)"
-        output += ('$(eol)Enter "help COMMAND" for help on a command '
-                   'named "COMMAND".')
+                    color = "grn"
+
+                # format the entry for this command
+                output = "%s   $(%s)%s$(nrm) - %s$(eol)" % (
+                    output, color, abbrev, description)
+
+        # add a footer with instructions on getting additional information
+        output = ('%s $(eol)Enter "help COMMAND" for help on a command named '
+                  '"COMMAND".' % output)
 
     # send the accumulated output to the user
     actor.send(output)
diff --git a/mudpy/tests/selftest.py b/mudpy/tests/selftest.py
index ddb09f0..56549da 100644
--- a/mudpy/tests/selftest.py
+++ b/mudpy/tests/selftest.py
@@ -216,9 +216,11 @@ test_admin_help = (
 )
 
 test_abbrev = (
-    (0, "> ", "help mov"),
-    (0, r"Move in a specific direction\.", "mov north"),
-    (0, r"You exit to the north\.", ""),
+    (0, "> ", "h"),
+    (0, r"h\[elp\].*m\[ove\].*> ", "he mo"),
+    (0, r"Move in a specific direction\..*> ", "mov north"),
+    (0, r"You exit to the north\..*> ", "m south"),
+    (0, r"You exit to the south\..*> ", ""),
 )
 
 test_reload = (
-- 
2.11.0