clam

clam is a modern program launcher for MS-DOS written in x86 assembly. Originally written in QuickBasic 4.5 it has a light memory footprint, and it is easy to use.

Its only requirement is an IBM AT or later class machine (essentially anything that has a 286 processor or better).

Build

clam was written in the Turbo Assembler dialect, and can be built by invoking the following commands, assuming the Turbo Assembler binaries are in your PATH:

tasm /ml /m3 clam.asm
tlink /c /t clam.obj

The source files make the distinction between lowercase and uppercase symbols, so it's important to compile and link using the appropriate switches.

Setup

clam works by detecting all batch files in a specified folder. It's not necessary to do anything in particular to make batch files in that folder discoverable, but it's possible to specify a "title" in order to make them easier to identify. You can add a title to a batch file by writing in the first line the special comment :::, for example:

::: Planet X3
@echo off

c:\
cd \games\px3
call px3_cga.com

The folder is specified by providing its path as a command line argument:

clam c:\batch

Usage

clam behaves like a shell, and queries the program list each time the user inputs a keypress. clam searches for matches in both the program basename and title, if present, and if it finds some results, the first one is displayed next to the query:

@ pl_ (Planet X3)

where _ marks the cursor location. Basename matches take priority over title matches, so if you remember the batch filename, you are guaranteed that the first result will be the corresponding program.

Navigation

You can edit the query as you'd expect from a shell:

• ← and → move the cursor left and right
• HOME moves the cursor at the beginning of the line
• END moves the cursor at the end of the line
• DELETE deletes the character under the cursor
• BACKSPACE deletes the character before the cursor

You can also immediately quit clam by sending a CTRL + C combination.

If the query matches multiple results, you can also navigate the result set:

• ↓ or TAB move to the next result
• ↑ moves to the previous result

At last, ENTER executes the displayed program.

Virtual programs

Among the real programs, clam adds two virtual programs:

• EXIT returns to DOS
• LIST shows a list of the registered programs, including itself and EXIT

They can be queried as normal:

@ ex_ (Exit to DOS)

or you can use the special characters * and . to invoke LIST and EXIT respectively.