NAME
tblks – text data blocks

SYNOPSIS
include "tblks.m";
tblks := load Tblks Tblks–>PATH;
Str: adt {
s: string;
findr:      fn(s: self ref Str, pos: int, c: int, lim: int): int;
find:       fn(s: self ref Str, pos: int, c: int, lim: int): int;
};
Tblk:       adt {
b:     array of ref Str;
new: fn(s: string): ref Tblk;
pack:       fn(blks: self ref Tblk): ref Str;
ins: fn(blks: self ref Tblk, s: string, pos: int);
del: fn(blks: self ref Tblk, n: int, pos: int): string;
seek:       fn(blks: self ref Tblk, pos: int): (int, int);      # (index in b, off in Str)
blen:       fn(blks: self ref Tblk): int;
getc:       fn(blks: self ref Tblk, pos: int): int;
gets:       fn(blks: self ref Tblk, pos: int, nr: int): string;
dump:       fn(blks: self ref Tblk);
};
init:           fn(sysm: Sys, strm: String, e: Error, dbg: int);
fixpos:          fn(pos: int, n: int): int;
fixposins:           fn(pos: int, inspos: int, n: int): int;
fixposdel:           fn(pos: int, delpos: int, n: int): int;
strstr:          fn(s1, s2: string): int;
strchr:          fn(s : string, c : int) : int;
dtxt:           fn(s: string): string;

DESCRIPTION
Tblks provides support for text handling. The Tblk data type represents text. It is organized as an array of strings, Tblk.b, making up the whole text. To avoid too much string copying, an auxiliary Str data type is used to keep references to strings.

Init should be called before using the module. It receives pointers to auxiliary modules loaded by the client program including sys(2), string(2), and error(2).

Tblk.new creates a new Tblk and returns a reference to it. The argument s represents initial contents for the text.

Tblk.pack packs all the strings in a single Str. After calling pack the single string (returned by the function) can be used to operate on the text using standard Limbo utilities. Various functions from the module may call pack when convenient.

Tblk.ins inserts s at pos in the text; Tblk.del deletes n runes starting at pos in the text (it returns the deleted string).

Tblk.seek translates a position pos into a couple of indexes: one locating the string in Tblk.b containing the position; another locating the rune within that string.

Tblk.len returns the number of runes in the text.

Tblk.getc returns a single rune at pos from the text and Tblk.gets returns a substring starting at pos and consisting of nr runes.

The auxiliary Str.find and Str.findr may be used to locate a rune c in the string given, not passing lim runes.

Other auxiliary functions like strchr and strstr are provided by the module for compatibility.

Fixpos ensures that n is in range (adjusting it if needed). Fixposins adjusts pos assuming that n runes have been inserted at inspos so that it refers to the same (relative) place in the text. Fixposdel is similar but adjusts for deletions.

Dtxt returns a short string useful to print any string for debugging.

EXAMPLE
See the source for olive(1) as an example of use.

SOURCE
/usr/octopus/port/lib/tblks.b