ref: d916a4c3823f55227ffae35738c2497256e307b5
dir: /appl/cmd/sh/regex.b/
implement Shellbuiltin;
include "sys.m";
sys: Sys;
include "draw.m";
include "sh.m";
sh: Sh;
Listnode, Context: import sh;
myself: Shellbuiltin;
include "regex.m";
regex: Regex;
initbuiltin(ctxt: ref Context, shmod: Sh): string
{
sys = load Sys Sys->PATH;
sh = shmod;
myself = load Shellbuiltin "$self";
if (myself == nil)
ctxt.fail("bad module", sys->sprint("regex: cannot load self: %r"));
regex = load Regex Regex->PATH;
if (regex == nil)
ctxt.fail("bad module",
sys->sprint("regex: cannot load %s: %r", Regex->PATH));
ctxt.addbuiltin("match", myself);
ctxt.addsbuiltin("re", myself);
return nil;
}
getself(): Shellbuiltin
{
return myself;
}
runbuiltin(ctxt: ref Context, nil: Sh,
argv: list of ref Listnode, nil: int): string
{
case (hd argv).word {
"match" =>
return builtin_match(ctxt, argv);
}
return nil;
}
whatis(nil: ref Sh->Context, nil: Sh, nil: string, nil: int): string
{
return nil;
}
runsbuiltin(ctxt: ref Context, nil: Sh,
argv: list of ref Listnode): list of ref Listnode
{
name := (hd argv).word;
case name {
"re" =>
return sbuiltin_re(ctxt, argv);
}
return nil;
}
sbuiltin_re(ctxt: ref Context, argv: list of ref Listnode): list of ref Listnode
{
if (tl argv == nil)
ctxt.fail("usage", "usage: re (g|v|s|sg|m|mg|M) arg...");
argv = tl argv;
w := (hd argv).word;
case w {
"g" or
"v" =>
return sbuiltin_sel(ctxt, argv, w == "v");
"s" or
"sg" =>
return sbuiltin_sub(ctxt, argv, w == "sg");
"m" =>
return sbuiltin_match(ctxt, argv, 0);
"mg" =>
return sbuiltin_gmatch(ctxt, argv);
"M" =>
return sbuiltin_match(ctxt, argv, 1);
* =>
ctxt.fail("usage", "usage: re (g|v|s|sg|m|mg|M) arg...");
return nil;
}
}
sbuiltin_match(ctxt: ref Context, argv: list of ref Listnode, aflag: int): list of ref Listnode
{
if (len argv != 3)
ctxt.fail("usage", "usage: re " + (hd argv).word + " arg");
argv = tl argv;
re := getregex(ctxt, word(hd argv), aflag);
w := word(hd tl argv);
a := regex->execute(re, w);
if (a == nil)
return nil;
ret: list of ref Listnode;
for (i := len a - 1; i >= 0; i--)
ret = ref Listnode(nil, elem(a, i, w)) :: ret;
return ret;
}
sbuiltin_gmatch(ctxt: ref Context, argv: list of ref Listnode): list of ref Listnode
{
if (len argv != 3)
ctxt.fail("usage", "usage: re mg arg");
argv = tl argv;
re := getregex(ctxt, word(hd argv), 0);
w := word(hd tl argv);
ret, nret: list of ref Listnode;
beg := 0;
while ((a := regex->executese(re, w, (beg, len w), beg == 0, 1)) != nil) {
(s, e) := a[0];
ret = ref Listnode(nil, w[s:e]) :: ret;
if (s == e)
break;
beg = e;
}
for (; ret != nil; ret = tl ret)
nret = hd ret :: nret;
return nret;
}
sbuiltin_sel(ctxt: ref Context, argv: list of ref Listnode, vflag: int): list of ref Listnode
{
cmd := (hd argv).word;
argv = tl argv;
if (argv == nil)
ctxt.fail("usage", "usage: " + cmd + " regex [arg...]");
re := getregex(ctxt, word(hd argv), 0);
ret, nret: list of ref Listnode;
for (argv = tl argv; argv != nil; argv = tl argv)
if (vflag ^ (regex->execute(re, word(hd argv)) != nil))
ret = hd argv :: ret;
for (; ret != nil; ret = tl ret)
nret = hd ret :: nret;
return nret;
}
sbuiltin_sub(ctxt: ref Context, argv: list of ref Listnode, gflag: int): list of ref Listnode
{
cmd := (hd argv).word;
argv = tl argv;
if (argv == nil || tl argv == nil)
ctxt.fail("usage", "usage: " + cmd + " regex subs [arg...]");
re := getregex(ctxt, word(hd argv), 1);
subs := word(hd tl argv);
ret, nret: list of ref Listnode;
for (argv = tl tl argv; argv != nil; argv = tl argv)
ret = ref Listnode(nil, substitute(word(hd argv), re, subs, gflag).t1) :: ret;
for (; ret != nil; ret = tl ret)
nret = hd ret :: nret;
return nret;
}
builtin_match(ctxt: ref Context, argv: list of ref Listnode): string
{
if (tl argv == nil)
ctxt.fail("usage", "usage: match regexp [arg...]");
re := getregex(ctxt, word(hd tl argv), 0);
for (argv = tl tl argv; argv != nil; argv = tl argv)
if (regex->execute(re, word(hd argv)) == nil)
return "no match";
return nil;
}
substitute(w: string, re: Regex->Re, subs: string, gflag: int): (int, string)
{
matched := 0;
s := "";
beg := 0;
do {
a := regex->executese(re, w, (beg, len w), beg == 0, 1);
if (a == nil)
break;
matched = 1;
s += w[beg:a[0].t0];
for (i := 0; i < len subs; i++) {
if (subs[i] != '\\' || i == len subs - 1)
s[len s] = subs[i];
else {
c := subs[++i];
if (c < '0' || c > '9')
s[len s] = c;
else
s += elem(a, c - '0', w);
}
}
beg = a[0].t1;
if (a[0].t0 == a[0].t1)
break;
} while (gflag && beg < len w);
return (matched, s + w[beg:]);
}
elem(a: array of (int, int), i: int, w: string): string
{
if (i < 0 || i >= len a)
return nil; # XXX could raise failure here. (invalid backslash escape)
(s, e) := a[i];
if (s == -1)
return nil;
return w[s:e];
}
# XXX could do regex caching here if it was worth it.
getregex(ctxt: ref Context, res: string, flag: int): Regex->Re
{
(re, err) := regex->compile(res, flag);
if (re == nil)
ctxt.fail("bad regex", "regex: bad regex \"" + res + "\": " + err);
return re;
}
word(n: ref Listnode): string
{
if (n.word != nil)
return n.word;
if (n.cmd != nil)
n.word = sh->cmd2string(n.cmd);
return n.word;
}