Getting started with Base24 development. TAL tutorial

Posted on 7th Jun 2017 1132 views

First program in TAL: the "hello world".
The code is below, we are going to compile it.
Compiling is done in a separate article, in this one we only focus on the code.
TAL stands fro Transaction Application Language, and you can expect that the language is sort of dedicated to working with data and processing data.
We need to explain the header here:

?nocode, inspect, symbols

This compiler directive contains 3 directives:
nocode: Lists instruction codes in octal format after each procedure
inspect: INSPECT sets the Inspect product as the default debugger for the object file
symbols: SYMBOLS saves symbols in a symbol table (for Inspect symbolic debugging) in the object file. The default is NOSYMBOLS

[break] More header:

?nolist, source $system.system.extdecs0(
? file_open_
? file_close_
? initializer
? writex
? process_getinfo_)

This compiler directive contains several directives:
nolist: NOLIST suppresses listing of sourced-in procedures
extdecs: EXTDECS is a file, provided by the operating system, that contains external declarations for system procedures. System procedures, for example, manage files, activate and terminate programs, and monitor the operations of processes.

?nocode, inspect, symbols

?nolist, source $system.system.extdecs0(
? file_open_
? file_close_
? initializer
? writex
? process_getinfo_)

?list

literal maxlen = 256;

proc startup_proc(rucb, passthru, message, msglen, match) variable;
int .rucb, .passthru, .message, msglen, match;
    begin
    end;

proc param_proc(rucb, passthru, message, msglen, match) variable;
int .rucb, .passthru, .message, msglen, match;
    begin
    end;

proc assign_proc(rucb, passthru, message, msglen, match) variable;
int .rucb, .passthru, .message, msglen, match;
    begin
    end;

proc hello_w main;
    begin
    int term_length, termnum, count;
    string .terminal_name[0:maxlen - 1], .sbuffer[0:maxlen - 1];

    call initializer(,, startup_proc, param_proc, assign_proc,,);
    call process_getinfo_(,,,,, terminal_name:maxlen, term_length);
    call file_open_(terminal_name:term_length, termnum);
    sbuffer ':=' "Hello world!";
    count := 12;
    call writex(termnum, sbuffer, count);
    call file_close_(termnum);
    end;