/ 
CPU-Z80-Assembler-2.03
River stage one • 1 direct dependent • 1 total dependent
/ CPU::Z80::Assembler::Lexer

NAME

CPU::Z80::Assembler::Lexer - Scanner for the Z80 assembler

SYNOPSIS

use CPU::Z80::Assembler::Lexer;
use HOP::Stream 'drop';

open($fh, $file1) or die;
my $stream = z80lexer("#include 'file2'\n", sub {<$fh>});

DESCRIPTION

This module provides a scanner to split the input source into tokens for the assembler. The scanner calls z80pp from CPU::Z80::Assembler::Macro to handle macro pre-processing, i.e. the returned tokens are already the result of macro expansion.

EXPORTS

By default the 'z80lexer' subroutine is exported. To disable that, do:

use CPU::Z80::Assembler::Lexer ();

FUNCTIONS

z80lexer

This takes as parameter a list of either text strings to parse, or iterators that return text strings to parse.

The result is a HOP::Stream that retrieves the next lexical token by each drop($stream).

Preprocessing

The following preprocessor-like lines are processed by the lexer:

%line N+M FILE

nasm-like line directive, telling that the next input line is line N from file FILE, followed by lines N+M, N+2*M, ... This information is used to generate error messages. Usefull to assemble a file preprocessed by nasm.

#line N "FILE"

cpp-like line directive, telling that the next input line is line N from file FILE, followed by lines N+1, N+2, ... This information is used to generate error messages. Usefull to assemble a file preprocessed by cpp.

include 'FILE'
include "FILE"
include <FILE>
%include ...
#include ...

nasm/cpp-like include directive, asking to insert the contents of the given file in the input stream. The Lexer inserts %line directives to synchronize file positions before and after the file inclusion.

The easiest form to ask z80asm to assemble a file is to write:

z80asm("include 'FILE'");

All the other preprocessor-like lines are ignored, i.e. lines starting with '#' or '%'.

TOKENS

The following tokens are returned by the stream:

["LINE", $line_text, $line_nr, $file]

Indicates that the next tokens belong to the given file, and line number, and contains the whole line text. This token is usefull to remember the current location in the source file, to show in listings or error messages.

[reserved, reserved]

All the reserved words and symbols are returned in lower case letters, e.g. ["nop", "nop"], or ["+", "+"].

["STRING", $string]

Single or double quoted strings are returned, including the quotes. The quote character cannot be used inside the string.

["NAME", $name]

All program identifiers, including '$'. The case is preserved, i.e. case-sensitive for labels, insensitive for assembly reserved words.

["NUMBER", $number]

Numbers are returned either in decimal, hexadecimal in the form 0x****, or binary in the form 0b****. The forms 0****H is replaced into 0x****, and the form 0****B into 0b****.

BUGS and FEEDBACK

See CPU::Z80::Assembler.

SEE ALSO

HOP::Stream CPU::Z80::Assembler::Macro CPU::Z80::Assembler

AUTHORS, COPYRIGHT and LICENCE

See CPU::Z80::Assembler.