On Thu, 17 Sep 2009 15:02:21 +0200, Adrian Neumann wrote:

You do

...

:l Data.Char

That command didn't work; see the following results: --8<---------------cut here---------------start------------->8--- Hugs>:| Data.Char Command not recognised. Type :? for help Hugs> --8<---------------cut here---------------end--------------->8--- -- Benjamin L. Russell

As far as I know you can't have multiple loaded modules unless you put them in a file and load that.

Regards,

Adrian

Benjamin L.Russell schrieb:

...

My apologies if this is an extremely elementary question, but I am having difficulties in importing the Data.Char library in Hugs.

In GHCi, the command "import Data.Char" works correctly, as follows:

--8<---------------cut here---------------start------------->8--- GHCi, version 6.10.3: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help.

Prelude> import Data.Char Prelude Data.Char> --8<---------------cut here---------------end--------------->8---

However, in Hugs, the same command fails with an error, as follows:

--8<---------------cut here---------------start------------->8--- __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2005 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Bugs: http://hackage.haskell.org/trac/hugs || || Version: 20051031 _________________________________________

Haskell 98 mode: Restart with command line option -98 to enable extensions

Type :? for help Hugs> import Data.Char ERROR - Syntax error in expression (unexpected keyword "import") Hugs> --8<---------------cut here---------------end--------------->8---

Does anybody know how to import the Data.Char library in Hugs?

-- Benjamin L. Russell

-- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^

Am Freitag 18 September 2009 08:05:46 schrieb Benjamin L.Russell:

Incidentally, if WinHugs cannot have multiple loaded modules unless they are put in a file and loaded therein, then what is the difference between the ":l" (a colon followed by a lowercase 'L') and ":a" (a colon followed by a lowercase 'A') commands?

The difference is that :load loads one module (and its imports) and forgets previously loaded modules, while :also doesn't forget the previously loaded modules. So if you first load a large project (A), evaluate some expressions in that context, then switch to a different project (B), and then switch back, if you use A> :a B B> some expression some result B> :m A A> the last A> prompt should be there pretty immediately, while in A> :l B B> some expression some result B> :l A A> the last A> prompt will take a while, since the entire project has to be lexed, parsed and compiled (to whatever intermediate representation Hugs uses) again.

On Thu, 17 Sep 2009 15:04:07 +0200, Daniel Fischer wrote:

Am Donnerstag 17 September 2009 14:41:47 schrieb Benjamin L.Russell:

...

My apologies if this is an extremely elementary question, but I am having difficulties in importing the Data.Char library in Hugs.

Hugs> :a Data.Char Data.Char>

Thank you; that was exactly the information for which I was looking. Incidentally, what option name does 'a' represent? That one doesn't appear when I type ":?." Shouldn't it appear in that list? -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^

On Fri, 18 Sep 2009 04:52:17 +0200, Daniel Fischer wrote:

Am Freitag 18 September 2009 04:27:31 schrieb Benjamin L.Russell:

...

On Thu, 17 Sep 2009 15:04:07 +0200, Daniel Fischer

wrote:

...

Am Donnerstag 17 September 2009 14:41:47 schrieb Benjamin L.Russell:

...

My apologies if this is an extremely elementary question, but I am having difficulties in importing the Data.Char library in Hugs.

Hugs> :a Data.Char Data.Char>

Thank you; that was exactly the information for which I was looking.

Incidentally, what option name does 'a' represent? That one doesn't appear when I type ":?." Shouldn't it appear in that list?

It should, and it does for me (hugs september 2006):

Hugs> :? LIST OF COMMANDS: Any command may be abbreviated to :c where c is the first character in the full name.

:load <filenames> load modules from specified files :load clear all files except prelude :also <filenames> read additional modules <--- There :reload repeat last load command

Oops; you're right: The structure of the two commands above it was the following:

:load <filenames> load modules from specified files :load clear all files except prelude

Apparently, for some reason, when I tried to scan through the list, I subconsciously grouped the two commands below similarly:

:also <filenames> read additional modules :reload repeat last load command

Therefore, I somehow only read the second line of what I thought was a structurally similar second group, and therefore noticed the ":reload," but not the ":also," expecting the command above it to be ":reload <filenames>." I probably should have either read more slowly (I was rushing out to lunch at the time), or somehow avoided unconsciously assuming patterns that didn't exist. Too much mental pattern-matching ;-).

Unfortunately, Hugs' behaviour is much less convenient than ghci's:

Hugs> :also Data.Char SimplTest SimplTest> ord 'a' ERROR - Undefined variable "ord" SimplTest> Data.Char.ord 'a' ERROR - Undefined qualified variable "Data.Char.ord"

You can't directly use it, neither qualified nor unqualified, you have to switch contexts with :m(odule):

SimplTest> :m Data.Char Data.Char> ord 'a' 97 Data.Char> :m SimplTest SimplTest> filter (test 4) $ digl 3 [[0,0,0],[0,1,4],[0,2,8],[1,4,0],[1,5,4],[1,6,8],[2,8,0],[2,9,4]]

Interesting; what happens if I then need to use a higher-order function composed of other functions, some of which are from different modules, interactively? -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^