ref: 21b91ad9fa7ae830272dc67fbe3150dc30921702
dir: /libregex/compile.myr/
use std
use "types.use"
use "ranges.use"
pkg regex =
const parse : (re : byte[:] -> std.result(ast#, status))
const compile : (re : byte[:] -> std.result(regex#, status))
const dbgcompile : (re : byte[:] -> std.result(regex#, status))
const free : (re : regex# -> void)
const failmsg : (st : status -> byte[:])
;;
type parseresult = union
`Some ast#
`None
`Fail status
;;
/* Compiles a pattern into a regex */
const compile = {pat
-> regexcompile(std.mk([.pat = pat, .nmatch = 1]), 0)
}
const parse = {pat
var re
re = std.mk([.pat = pat, .nmatch = 1])
match regexparse(re)
| `None: -> `std.Fail `Incomplete
| `Fail f: -> `std.Fail f
| `Some t:
if re.pat.len > 0
-> `std.Fail `Incomplete
else
-> `std.Ok t
;;
;;
}
/* Compiles a pattern into a debug regex. This can be verbose. */
const dbgcompile = {pat
var re
re = std.mk([.pat = pat, .nmatch = 1, .debug = true])
-> regexcompile(re, 0)
}
/* compiles a pattern into an allocated regex */
const regexcompile = {re, id
match regexparse(re)
| `None: -> `std.Fail (`Incomplete)
| `Fail f: -> `std.Fail f
| `Some t:
/*
we can stop early if we get
an incorrectly encoded char
*/
if re.pat.len > 0
astfree(t)
-> `std.Fail (`Incomplete)
;;
dump(re, t, 0)
append(re, `Ilbra 0)
gen(re, t)
append(re, `Irbra 0)
append(re, `Imatch id)
idump(re)
astfree(t)
-> `std.Ok re
;;
-> `std.Fail (`Noimpl)
}
const free = {re
/* all the threads should be dead,
so we shouldn't have to free any*/
std.slfree(re.prog)
std.free(re)
}
/* generates bytecode from an AST */
const gen = {re, t
match t#
|`Alt (a, b): genalt(re, a, b)
|`Cat (a, b): gen(re, a); gen(re, b)
/* repetition */
|`Star a: genstar(re, a, false)
|`Rstar a: genstar(re, a, true)
|`Plus a: gen(re, a); genstar(re, a, false)
|`Rplus a: gen(re, a); genstar(re, a, true)
|`Quest a: genquest(re, a)
/* end matches */
|`Byte b: append(re, `Ibyte b)
|`Chr c: genchar(re, c)
|`Ranges sl: genranges(re, sl)
/* meta */
|`Bol: append(re, `Ibol)
|`Eol: append(re, `Ibol)
|`Bow: append(re, `Ibow)
|`Eow: append(re, `Ieow)
|`Cap (m, a):
append(re, `Ilbra m)
gen(re, a)
append(re, `Irbra m)
;;
-> re.proglen
}
const genranges = {re, sl
var lbuf : byte[4], hbuf : byte[4], boundbuf : byte[4]
var lsz, hsz, bsz, i
var rt : rangetrie#
/* generate a trie of ranges */
rt = std.zalloc()
for r in sl
/*
encode:
lo => bounds[loidx] - 1
bounds[loidx] => bounds[loidx + 1] - 1
...
bounds[hiidx - 1] => hi
*/
lsz = std.encode(lbuf[:], r[0])
hsz = std.encode(hbuf[:], r[1])
for i = lsz; i < hsz; i++
bsz = bound(boundbuf[:], i, 0xff)
rtinsert(rt, lbuf[:lsz], boundbuf[:bsz])
lsz = bound(lbuf[:], i + 1, 0x00)
;;
rtinsert(rt, lbuf[:lsz], hbuf[:hsz])
;;
if re.debug
rtdump(rt, 0)
;;
rangegen(re, rt, rt.ranges, rt.link, rangeprogsize(rt) + re.proglen)
rtfree(rt)
-> re.proglen
}
const bound = {buf, len, fill
var i, s
if len == 1
buf[0] = 0x7f
else
s = len castto(byte)
buf[0] = (0xff << (8 - s)) | (fill >> (s + 1))
for i = 1; i < len; i++
buf[i] = 0x80 | (fill >> 2)
;;
;;
-> len
}
type rangetrie = struct
ranges : (byte, byte)[:]
link : rangetrie#[:]
end : bool
;;
const rtdump = {rt, ind
var i
var l, h
indent(ind)
std.put("Range (end = {}) {{\n", rt.end)
for i = 0; i < rt.ranges.len; i++
indent(ind + 1)
(l, h) = rt.ranges[i]
std.put("0x{x}-0x{x}: \n", l, h)
rtdump(rt.link[i], ind + 1)
;;
indent(ind)
std.put("}\n")
}
const indent = {ind
var i
for i = 0; i < ind; i++
std.put("\t")
;;
}
const rtinsert = {rt, lo, hi
var a, b
var n
std.assert(lo.len == hi.len, "range sizes differ")
if lo.len == 0
rt.end = true
->
;;
n = rt.ranges.len
if n == 0
rt.ranges = std.slpush(rt.ranges, (lo[0], hi[0]))
rt.link = std.slpush(rt.link, std.zalloc())
else
/*
this is a safe way to compare because we know that ranges
should always be coming in ordered. This means that equal
values will be added one after the other.
*/
(a, b) = rt.ranges[n - 1]
if a != lo[0] || b != hi[0]
rt.ranges = std.slpush(rt.ranges, (lo[0], hi[0]))
rt.link = std.slpush(rt.link, std.zalloc())
;;
;;
rtinsert(rt.link[rt.link.len - 1], lo[1:], hi[1:])
}
const rtfree = {rt
for l in rt.link
rtfree(l)
;;
std.slfree(rt.link)
std.slfree(rt.ranges)
std.free(rt)
}
const rangegen = {re, rt, ranges, links, end
var alt, l0, l1, l2
var a, b
var n
n = ranges.len
if n == 0
-> re.proglen
elif n == 1
(a, b) = ranges[0]
append(re, `Irange (a, b))
if links[0].end
if links[0].ranges.len > 0
append(re, `Ifork (re.prog.len + 1, end))
else
append(re, `Ijmp end)
;;
;;
rangegen(re, links[0], links[0].ranges, links[0].link, end)
else
alt = re.proglen
l0 = append(re, `Ifork (-1, -1))
l1 = rangegen(re, rt, ranges[0:n/2], links[0:n/2], end)
l2 = rangegen(re, rt, ranges[n/2:n], links[n/2:n], end)
re.prog[alt] = `Ifork (l0, l1)
;;
-> re.proglen
}
const rangeprogsize = {rt
var sz
if rt.ranges.len == 0
sz = 0
else
sz = 2*rt.ranges.len - 1
for l in rt.link
sz += rangeprogsize(l)
;;
;;
if rt.end
sz += 1
;;
-> sz
}
/* calculates the forward jump distance for a utf8 character range */
const jmpdist = {n
var d
var i
d = n - 1
for i = n - 1; i > 0; i--
d += i
;;
-> d
}
/* generates an alternation */
const genalt = {re, l, r
var alt
var jmp
var l0
var l1
var l2
alt = re.proglen
l0 = append(re, `Ifork (-1, -1)) /* needs to be replaced */
gen(re, l)
jmp = re.proglen
l1 = append(re, `Ijmp -1) /* needs to be replaced */
l2 = gen(re, r)
re.prog[alt] = `Ifork(l0, l1)
re.prog[jmp] = `Ijmp l2
-> re.proglen
}
/* generates a repetition operator */
const genstar = {re, rep, reluct
var alt
var jmp
var l0
var l1
var l2
l0 = re.proglen
alt = re.proglen
l1 = append(re, `Ifork (-1, -1)) /* needs to be replaced */
jmp = gen(re, rep)
l2 = append(re, `Ijmp -1)
/* reluctant matches should prefer jumping to the end. */
if reluct
re.prog[alt] = `Ifork (l2, l1)
else
re.prog[alt] = `Ifork (l1, l2)
;;
re.prog[jmp] = `Ijmp l0
-> re.proglen
}
/* generates a question mark operator */
const genquest = {re, q
var alt
var l0
var l1
alt = re.proglen
l0 = append(re, `Ifork (-1, -1)) /* needs to be replaced */
l1 = gen(re, q)
re.prog[alt] = `Ifork (l0, l1)
-> re.proglen
}
/* generates a single char match */
const genchar = {re, c
var b : byte[4]
var n
var i
n = std.encode(b[:], c)
std.assert(n > 0 && n < 4, "non-utf character in regex\n")
for i = 0; i < n; i++
append(re, `Ibyte b[i])
;;
-> re.proglen
}
/* appends an instructon to an re program */
const append = {re, insn
if re.proglen == re.prog.len
re.prog = std.slgrow(re.prog, std.max(1, 2*re.proglen))
;;
re.prog[re.proglen] = insn
re.proglen++
-> re.proglen
}
/* instruction dump */
const idump = {re
var i
if !re.debug
->
;;
for i = 0; i < re.proglen; i++
std.put("{}:\t", i)
match re.prog[i]
/* Char matching. Consume exactly one byte from the string. */
| `Ibyte b: std.put("`Ibyte {} ({})\n", b, b castto(char))
| `Irange (start, end):
std.put("`Irange ({},{})", start, end)
if std.isalnum(start castto(char)) && std.isalnum(end castto(char))
std.put("\t/* {}-{} */", start castto(char), end castto(char))
;;
std.put("\n")
/* capture groups */
| `Ilbra m: std.put("`Ilbra {}\n", m)
| `Irbra m: std.put("`Irbra {}\n", m)
/* anchors */
| `Ibol: std.put("`Ibol\n")
| `Ieol: std.put("`Ieol\n")
| `Ibow: std.put("`Ibow\n")
| `Ieow: std.put("`Ieow\n")
/* control flow */
| `Ifork (lip, rip): std.put("`Ifork ({},{})\n", lip, rip)
| `Ijmp ip: std.put("`Ijmp {}\n", ip)
| `Imatch id: std.put("`Imatch {}\n", id)
;;
;;
}
/* AST dump */
const dump = {re, t, indent
var i
if !re.debug
->
;;
for i = 0; i < indent; i++
std.put(" ")
;;
match t#
| `Alt (a, b):
std.put("Alt\n")
dump(re, a, indent + 1)
dump(re, b, indent + 1)
| `Cat (a, b):
std.put("Cat\n")
dump(re, a, indent + 1)
dump(re, b, indent + 1)
/* repetition */
| `Star a:
std.put("Star\n")
dump(re, a, indent + 1)
| `Rstar a:
std.put("Rstar\n")
dump(re, a, indent + 1)
| `Plus a:
std.put("Plus\n")
dump(re, a, indent + 1)
| `Rplus a:
std.put("Rplus\n")
dump(re, a, indent + 1)
| `Quest a:
std.put("Quest\n")
dump(re, a, indent + 1)
| `Bol:
std.put("Bol\n")
| `Eol:
std.put("Eol\n")
| `Bow:
std.put("Bow\n")
| `Eow:
std.put("Eow\n")
/* end matches */
| `Byte b:
std.put("Byte {}\n", b)
| `Chr c:
std.put("Char {}\n", c)
| `Ranges rl:
std.put("Ranges")
for r in rl
for i = 0; i < indent + 1; i++
std.put(" ")
;;
std.put("\t({}-{})\n", r[0], r[1])
;;
/* meta */
| `Cap (m, a):
std.put("Cap {}\n", m)
dump(re, a, indent + 1)
;;
}
/* parses an expression */
const regexparse = {re
match altexpr(re)
| `Some t:
if re.pat.len == 0
-> `Some t
else
astfree(t)
-> `Fail `Incomplete
;;
| `None:
-> `None
| `Fail st:
-> `Fail st
;;
}
const altexpr = {re
var ret
match catexpr(re)
| `Some t:
ret = t
if matchc(re, '|')
match altexpr(re)
| `Some rhs:
ret = mk(`Alt (ret, rhs))
| `None:
astfree(ret)
-> `Fail (`Incomplete)
| `Fail f:
-> `Fail f
;;
;;
| other:
-> other
;;
-> `Some ret
}
const catexpr = {re
var ret
match repexpr(re)
| `Some t:
ret = t
match catexpr(re)
| `Some rhs:
ret = mk(`Cat (t, rhs))
| `Fail f: -> `Fail f
| `None: /* nothing */
;;
| other:
-> other
;;
-> `Some ret
}
const repexpr = {re
var ret
match baseexpr(re)
| `Some t:
if matchc(re, '*')
if matchc(re, '?')
ret = mk(`Rstar t)
else
ret = mk(`Star t)
;;
elif matchc(re, '+')
if matchc(re, '?')
ret = mk(`Rplus t)
else
ret = mk(`Plus t)
;;
elif matchc(re, '?')
ret = mk(`Quest t)
else
ret = t
;;
| other:
-> other
;;
-> `Some ret
}
const baseexpr = {re
var ret, m
if re.pat.len == 0
-> `None
;;
match peekc(re)
/* lower prec operators */
| '|': -> `None
| ')': -> `None
| '*': -> `Fail `Badrep
| '+': -> `Fail `Badrep
| '?': -> `Fail `Badrep
| '[': -> chrclass(re)
| '.': getc(re); ret = mk(`Ranges std.slpush([][:], [0, std.Maxcharval]))
| '^': getc(re); ret = mk(`Bol)
| '$': getc(re); ret = mk(`Eol)
| '(':
m = re.nmatch++
getc(re)
match altexpr(re)
| `Some s:
if matchc(re, ')')
-> `Some mk(`Cap (m, s))
else
-> `Fail `Unbalanced
;;
| `None: -> `Fail `Emptyparen
| `Fail st: -> `Fail st
;;
| '\\':
getc(re) /* consume the slash */
if re.pat.len == 0
-> `Fail `Incomplete
;;
-> escaped(re)
| c:
getc(re)
ret = mk(`Chr c)
;;
-> `Some ret
}
const escaped = {re
var ret
match getc(re)
/* character classes */
| 'd': ret = `Some mk(`Ranges std.sldup(_ranges.tabasciidigit[:]))
| 'x': ret = `Some mk(`Ranges std.sldup(_ranges.tabasciixdigit[:]))
| 's': ret = `Some mk(`Ranges std.sldup(_ranges.tabasciispace[:]))
| 'w': ret = `Some mk(`Ranges std.sldup(_ranges.tabasciiword[:]))
| 'h': ret = `Some mk(`Ranges std.sldup(_ranges.tabasciiblank[:]))
/* negated character classes */
| 'W': ret = `Some mk(`Ranges negate(_ranges.tabasciiword[:]))
| 'S': ret = `Some mk(`Ranges negate(_ranges.tabasciispace[:]))
| 'D': ret = `Some mk(`Ranges negate(_ranges.tabasciidigit[:]))
| 'X': ret = `Some mk(`Ranges negate(_ranges.tabasciixdigit[:]))
| 'H': ret = `Some mk(`Ranges negate(_ranges.tabasciiblank[:]))
/* unicode character classes */
| 'p': ret = unicodeclass(re, false)
| 'P': ret = unicodeclass(re, true)
/* operators that need an escape */
| '<': ret = `Some mk(`Bow)
| '>': ret = `Some mk(`Eow)
/* escaped metachars */
| '^': ret = `Some mk(`Chr '^')
| '$': ret = `Some mk(`Chr '$')
| '.': ret = `Some mk(`Chr '.')
| '+': ret = `Some mk(`Chr '+')
| '?': ret = `Some mk(`Chr '?')
| chr: ret = `Fail `Badescape
;;
-> ret
}
const unicodeclass = {re, neg
var c, s
var tab
var t
var n
if re.pat.len == 0
-> `Fail (`Incomplete)
;;
n = 0
s = re.pat
/* either a single char pattern, or {pat} */
match getc(re)
| '{':
s = s[1:]
while re.pat.len > 0
c = getc(re)
if c == '}'
break
;;
n += std.charlen(c)
;;
| r:
n += std.charlen(r)
;;
s = s[:n]
/* letters */
if std.sleq(s, "L") || std.sleq(s, "Letter")
tab = _ranges.tabalpha[:]
elif std.sleq(s, "Lu") || std.sleq(s, "Uppercase_Letter")
tab = _ranges.tabupper[:]
elif std.sleq(s, "Ll") || std.sleq(s, "Lowercase_Letter")
tab = _ranges.tablower[:]
elif std.sleq(s, "Lt") || std.sleq(s, "Titlecase_Letter")
tab = _ranges.tablower[:]
/* numbers (incomplete) */
elif std.sleq(s, "N") || std.sleq(s, "Number")
tab = _ranges.tabdigit[:]
elif std.sleq(s, "Z") || std.sleq(s, "Separator")
tab = _ranges.tabspace[:]
elif std.sleq(s, "Zs") || std.sleq(s, "Space_Separator")
tab = _ranges.tabblank[:]
else
-> `Fail (`Badrange)
;;
if !neg
t = mk(`Ranges std.sldup(tab))
else
t = mk(`Ranges negate(tab))
;;
-> `Some t
}
const chrclass = {re
var rl, m, n
var neg
var t
/* we know we saw '[' on entry */
matchc(re, '[')
neg = false
if matchc(re, '^')
neg = true
;;
rl = rangematch(re, [][:])
while peekc(re) != ']' && re.pat.len > 0
rl = rangematch(re, rl)
;;
if !matchc(re, ']')
std.slfree(rl)
-> `Fail `Unbalanced
;;
std.sort(rl, {a, b;
if a[0] < b[0]
-> `std.Before
elif a[0] == b[0]
-> `std.Equal
else
-> `std.After
;;})
m = merge(rl)
std.slfree(rl)
if neg
n = negate(m)
std.slfree(m)
t = mk(`Ranges n)
else
t = mk(`Ranges m)
;;
-> `Some t
}
const rangematch = {re, sl
var lo
var hi
lo = getc(re)
if matchc(re, '-')
hi = getc(re)
if lo <= hi
-> std.slpush(sl, [lo, hi])
else
-> std.slpush(sl, [hi, lo])
;;
else
-> std.slpush(sl, [lo, lo])
;;
}
const negate = {rng
var start, end, next
var neg
neg = [][:]
start = 0
next = 0 /* if we have no ranges */
for r in rng
(end, next) = (r[0], r[1])
neg = std.slpush(neg, [start, end - 1])
start = next + 1
;;
neg = std.slpush(neg, [next + 1, std.Maxcharval])
-> neg
}
/* rl is a sorted list of ranges */
const merge = {rl
var lo, hi
var ret
if rl.len == 0
-> [][:]
;;
ret = [][:]
lo = rl[0][0]
hi = rl[0][1]
for r in rl[1:]
/* if it overlaps or abuts, merge */
if r[0] <= hi + 1
hi = r[1]
else
ret = std.slpush(ret, [lo, hi])
lo = r[0]
hi = r[1]
;;
;;
-> std.slpush(ret, [lo, hi])
}
const matchc = {re, c
var str
var chr
(chr, str) = std.striter(re.pat)
if chr != c
-> false
;;
re.pat = str
-> true
}
const getc = {re
var c
(c, re.pat) = std.striter(re.pat)
-> c
}
const peekc = {re
var c
var _
(c, _) = std.striter(re.pat)
-> c
}
const mk = {v
var t
t = std.alloc()
t# = v
-> t
}
const astfree = {t
match t#
| `Alt (a, b): astfree(a); astfree(b)
| `Cat (a, b): astfree(a); astfree(b)
/* repetition */
| `Star a: astfree(a)
| `Rstar a: astfree(a)
| `Plus a: astfree(a)
| `Rplus a: astfree(a)
| `Quest a: astfree(a)
/* end matches */
| `Byte b:
| `Chr c:
| `Ranges rl: std.slfree(rl)
/* meta */
| `Cap (m, a): astfree(a)
| _: /* other types have no suballocations */
;;
std.free(t)
}
const failmsg = {st
match st
| `Noimpl: -> "no implementation"
| `Incomplete: -> "regex ended before input fully parsed"
| `Unbalanced: -> "unbalanced bracket"
| `Emptyparen: -> "empty parentheses"
| `Badrep: -> "invalid repetition"
| `Badrange: -> "invalid range"
| `Badescape: -> "invalid escape code"
;;
}