#
#
# Nim's Runtime Library
# (c) Copyright 2012 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module contains helpers for parsing tokens, numbers, identifiers, etc.
##
## To unpack raw bytes look at the `streams <streams.html>`_ module.
{.deadCodeElim: on.} # dce option deprecated
{.push debugger:off .} # the user does not want to trace a part
# of the standard library!
include "system/inclrtl"
const
Whitespace = {' ', '\t', '\v', '\r', '\l', '\f'}
IdentChars = {'a'..'z', 'A'..'Z', '0'..'9', '_'}
IdentStartChars = {'a'..'z', 'A'..'Z', '_'}
## copied from strutils
proc toLower(c: char): char {.inline.} =
result = if c in {'A'..'Z'}: chr(ord(c)-ord('A')+ord('a')) else: c
proc parseHex*(s: string, number: var int, start = 0; maxLen = 0): int {.
rtl, extern: "npuParseHex", noSideEffect.} =
## Parses a hexadecimal number and stores its value in ``number``.
##
## Returns the number of the parsed characters or 0 in case of an error. This
## proc is sensitive to the already existing value of ``number`` and will
## likely not do what you want unless you make sure ``number`` is zero. You
## can use this feature to *chain* calls, though the result int will quickly
## overflow. Example:
##
## .. code-block:: nim
## var value = 0
## discard parseHex("0x38", value)
## assert value == 56
## discard parseHex("0x34", value)
## assert value == 56 * 256 + 52
## value = -1
## discard parseHex("0x38", value)
## assert value == -200
##
## If ``maxLen == 0`` the length of the hexadecimal number has no upper bound.
## Else no more than ``start + maxLen`` characters are parsed, up to the
## length of the string.
var i = start
var foundDigit = false
# get last index based on minimum `start + maxLen` or `s.len`
let last = min(s.len, if maxLen == 0: s.len else: i+maxLen)
if i+1 < last and s[i] == '0' and (s[i+1] in {'x', 'X'}): inc(i, 2)
elif i < last and s[i] == '#': inc(i)
while i < last:
case s[i]
of '_': discard
of '0'..'9':
number = number shl 4 or (ord(s[i]) - ord('0'))
foundDigit = true
of 'a'..'f':
number = number shl 4 or (ord(s[i]) - ord('a') + 10)
foundDigit = true
of 'A'..'F':
number = number shl 4 or (ord(s[i]) - ord('A') + 10)
foundDigit = true
else: break
inc(i)
if foundDigit: result = i-start
proc parseOct*(s: string, number: var int, start = 0, maxLen = 0): int {.
rtl, extern: "npuParseOct", noSideEffect.} =
## Parses an octal number and stores its value in ``number``. Returns
## the number of the parsed characters or 0 in case of an error.
##
## If ``maxLen == 0`` the length of the octal number has no upper bound.
## Else no more than ``start + maxLen`` characters are parsed, up to the
## length of the string.
var i = start
var foundDigit = false
# get last index based on minimum `start + maxLen` or `s.len`
let last = min(s.len, if maxLen == 0: s.len else: i+maxLen)
if i+1 < last and s[i] == '0' and (s[i+1] in {'o', 'O'}): inc(i, 2)
while i < last:
case s[i]
of '_': discard
of '0'..'7':
number = number shl 3 or (ord(s[i]) - ord('0'))
foundDigit = true
else: break
inc(i)
if foundDigit: result = i-start
proc parseBin*(s: string, number: var int, start = 0, maxLen = 0): int {.
rtl, extern: "npuParseBin", noSideEffect.} =
## Parses an binary number and stores its value in ``number``. Returns
## the number of the parsed characters or 0 in case of an error.
##
## If ``maxLen == 0`` the length of the binary number has no upper bound.
## Else no more than ``start + maxLen`` characters are parsed, up to the
## length of the string.
var i = start
var foundDigit = false
# get last index based on minimum `start + maxLen` or `s.len`
let last = min(s.len, if maxLen == 0: s.len else: i+maxLen)
if i+1 < last and s[i] == '0' and (s[i+1] in {'b', 'B'}): inc(i, 2)
while i < last:
case s[i]
of '_': discard
of '0'..'1':
number = number shl 1 or (ord(s[i]) - ord('0'))
foundDigit = true
else: break
inc(i)
if foundDigit: result = i-start
proc parseIdent*(s: string, ident: var string, start = 0): int =
## parses an identifier and stores it in ``ident``. Returns
## the number of the parsed characters or 0 in case of an error.
var i = start
if i < s.len and s[i] in IdentStartChars:
inc(i)
while i < s.len and s[i] in IdentChars: inc(i)
ident = substr(s, start, i-1)
result = i-start
proc parseIdent*(s: string, start = 0): string =
## parses an identifier and stores it in ``ident``.
## Returns the parsed identifier or an empty string in case of an error.
result = ""
var i = start
if i < s.len and s[i] in IdentStartChars:
inc(i)
while i < s.len and s[i] in IdentChars: inc(i)
result = substr(s, start, i-1)
proc parseToken*(s: string, token: var string, validChars: set[char],
start = 0): int {.inline, deprecated.} =
## parses a token and stores it in ``token``. Returns
## the number of the parsed characters or 0 in case of an error. A token
## consists of the characters in `validChars`.
##
## **Deprecated since version 0.8.12**: Use ``parseWhile`` instead.
var i = start
while i < s.len and s[i] in validChars: inc(i)
result = i-start
token = substr(s, start, i-1)
proc skipWhitespace*(s: string, start = 0): int {.inline.} =
## skips the whitespace starting at ``s[start]``. Returns the number of
## skipped characters.
while start+result < s.len and s[start+result] in Whitespace: inc(result)
proc skip*(s, token: string, start = 0): int {.inline.} =
## skips the `token` starting at ``s[start]``. Returns the length of `token`
## or 0 if there was no `token` at ``s[start]``.
while start+result < s.len and result < token.len and
s[result+start] == token[result]:
inc(result)
if result != token.len: result = 0
proc skipIgnoreCase*(s, token: string, start = 0): int =
## same as `skip` but case is ignored for token matching.
while start+result < s.len and result < token.len and
toLower(s[result+start]) == toLower(token[result]): inc(result)
if result != token.len: result = 0
proc skipUntil*(s: string, until: set[char], start = 0): int {.inline.} =
## Skips all characters until one char from the set `until` is found
## or the end is reached.
## Returns number of characters skipped.
while start+result < s.len and s[result+start] notin until: inc(result)
proc skipUntil*(s: string, until: char, start = 0): int {.inline.} =
## Skips all characters until the char `until` is found
## or the end is reached.
## Returns number of characters skipped.
while start+result < s.len and s[result+start] != until: inc(result)
proc skipWhile*(s: string, toSkip: set[char], start = 0): int {.inline.} =
## Skips all characters while one char from the set `token` is found.
## Returns number of characters skipped.
while start+result < s.len and s[result+start] in toSkip: inc(result)
proc parseUntil*(s: string, token: var string, until: set[char],
start = 0): int {.inline.} =
## parses a token and stores it in ``token``. Returns
## the number of the parsed characters or 0 in case of an error. A token
## consists of the characters notin `until`.
var i = start
while i < s.len and s[i] notin until: inc(i)
result = i-start
token = substr(s, start, i-1)
proc parseUntil*(s: string, token: var string, until: char,
start = 0): int {.inline.} =
## parses a token and stores it in ``token``. Returns
## the number of the parsed characters or 0 in case of an error. A token
## consists of any character that is not the `until` character.
var i = start
while i < s.len and s[i] != until: inc(i)
result = i-start
token = substr(s, start, i-1)
proc parseUntil*(s: string, token: var string, until: string,
start = 0): int {.inline.} =
## parses a token and stores it in ``token``. Returns
## the number of the parsed characters or 0 in case of an error. A token
## consists of any character that comes before the `until` token.
if until.len == 0:
token.setLen(0)
return 0
var i = start
while i < s.len:
if s[i] == until[0]:
var u = 1
while i+u < s.len and u < until.len and s[i+u] == until[u]:
inc u
if u >= until.len: break
inc(i)
result = i-start
token = substr(s, start, i-1)
proc parseWhile*(s: string, token: var string, validChars: set[char],
start = 0): int {.inline.} =
## parses a token and stores it in ``token``. Returns
## the number of the parsed characters or 0 in case of an error. A token
## consists of the characters in `validChars`.
var i = start
while i < s.len and s[i] in validChars: inc(i)
result = i-start
token = substr(s, start, i-1)
proc captureBetween*(s: string, first: char, second = '\0', start = 0): string =
## Finds the first occurrence of ``first``, then returns everything from there
## up to ``second`` (if ``second`` is '\0', then ``first`` is used).
var i = skipUntil(s, first, start)+1+start
result = ""
discard s.parseUntil(result, if second == '\0': first else: second, i)
{.push overflowChecks: on.}
# this must be compiled with overflow checking turned on:
proc rawParseInt(s: string, b: var BiggestInt, start = 0): int =
var
sign: BiggestInt = -1
i = start
if i < s.len:
if s[i] == '+': inc(i)
elif s[i] == '-':
inc(i)
sign = 1
if i < s.len and s[i] in {'0'..'9'}:
b = 0
while i < s.len and s[i] in {'0'..'9'}:
b = b * 10 - (ord(s[i]) - ord('0'))
inc(i)
while i < s.len and s[i] == '_': inc(i) # underscores are allowed and ignored
b = b * sign
result = i - start
{.pop.} # overflowChecks
proc parseBiggestInt*(s: string, number: var BiggestInt, start = 0): int {.
rtl, extern: "npuParseBiggestInt", noSideEffect.} =
## parses an integer starting at `start` and stores the value into `number`.
## Result is the number of processed chars or 0 if there is no integer.
## `EOverflow` is raised if an overflow occurs.
var res: BiggestInt
# use 'res' for exception safety (don't write to 'number' in case of an
# overflow exception):
result = rawParseInt(s, res, start)
number = res
proc parseInt*(s: string, number: var int, start = 0): int {.
rtl, extern: "npuParseInt", noSideEffect.} =
## parses an integer starting at `start` and stores the value into `number`.
## Result is the number of processed chars or 0 if there is no integer.
## `EOverflow` is raised if an overflow occurs.
var res: BiggestInt
result = parseBiggestInt(s, res, start)
if (sizeof(int) <= 4) and
((res < low(int)) or (res > high(int))):
raise newException(OverflowError, "overflow")
elif result != 0:
number = int(res)
proc parseSaturatedNatural*(s: string, b: var int, start = 0): int =
## parses a natural number into ``b``. This cannot raise an overflow
## error. Instead of an ``Overflow`` exception ``high(int)`` is returned.
## The number of processed character is returned.
## This is usually what you really want to use instead of `parseInt`:idx:.
## Example:
##
## .. code-block:: nim
## var res = 0
## discard parseSaturatedNatural("848", res)
## doAssert res == 848
var i = start
if i < s.len and s[i] == '+': inc(i)
if i < s.len and s[i] in {'0'..'9'}:
b = 0
while i < s.len and s[i] in {'0'..'9'}:
let c = ord(s[i]) - ord('0')
if b <= (high(int) - c) div 10:
b = b * 10 + c
else:
b = high(int)
inc(i)
while i < s.len and s[i] == '_': inc(i) # underscores are allowed and ignored
result = i - start
# overflowChecks doesn't work with BiggestUInt
proc rawParseUInt(s: string, b: var BiggestUInt, start = 0): int =
var
res = 0.BiggestUInt
prev = 0.BiggestUInt
i = start
if i < s.len and s[i] == '+': inc(i) # Allow
if i < s.len and s[i] in {'0'..'9'}:
b = 0
while i < s.len and s[i] in {'0'..'9'}:
prev = res
res = res * 10 + (ord(s[i]) - ord('0')).BiggestUInt
if prev > res:
return 0 # overflowChecks emulation
inc(i)
while i < s.len and s[i] == '_': inc(i) # underscores are allowed and ignored
b = res
result = i - start
proc parseBiggestUInt*(s: string, number: var BiggestUInt, start = 0): int {.
rtl, extern: "npuParseBiggestUInt", noSideEffect.} =
## parses an unsigned integer starting at `start` and stores the value
## into `number`.
## Result is the number of processed chars or 0 if there is no integer
## or overflow detected.
var res: BiggestUInt
# use 'res' for exception safety (don't write to 'number' in case of an
# overflow exception):
result = rawParseUInt(s, res, start)
number = res
proc parseUInt*(s: string, number: var uint, start = 0): int {.
rtl, extern: "npuParseUInt", noSideEffect.} =
## parses an unsigned integer starting at `start` and stores the value
## into `number`.
## Result is the number of processed chars or 0 if there is no integer or
## overflow detected.
var res: BiggestUInt
result = parseBiggestUInt(s, res, start)
when sizeof(BiggestUInt) > sizeof(uint) and sizeof(uint) <= 4:
if res > 0xFFFF_FFFF'u64:
raise newException(OverflowError, "overflow")
if result != 0:
number = uint(res)
proc parseBiggestFloat*(s: string, number: var BiggestFloat, start = 0): int {.
magic: "ParseBiggestFloat", importc: "nimParseBiggestFloat", noSideEffect.}
## parses a float starting at `start` and stores the value into `number`.
## Result is the number of processed chars or 0 if a parsing error
## occurred.
proc parseFloat*(s: string, number: var float, start = 0): int {.
rtl, extern: "npuParseFloat", noSideEffect.} =
## parses a float starting at `start` and stores the value into `number`.
## Result is the number of processed chars or 0 if there occurred a parsing
## error.
var bf: BiggestFloat
result = parseBiggestFloat(s, bf, start)
if result != 0:
number = bf
type
InterpolatedKind* = enum ## describes for `interpolatedFragments`
## which part of the interpolated string is
## yielded; for example in "str$$$var${expr}"
ikStr, ## ``str`` part of the interpolated string
ikDollar, ## escaped ``$`` part of the interpolated string
ikVar, ## ``var`` part of the interpolated string
ikExpr ## ``expr`` part of the interpolated string
iterator interpolatedFragments*(s: string): tuple[kind: InterpolatedKind,
value: string] =
## Tokenizes the string `s` into substrings for interpolation purposes.
##
## Example:
##
## .. code-block:: nim
## for k, v in interpolatedFragments(" $this is ${an example} $$"):
## echo "(", k, ", \"", v, "\")"
##
## Results in:
##
## .. code-block:: nim
## (ikString, " ")
## (ikExpr, "this")
## (ikString, " is ")
## (ikExpr, "an example")
## (ikString, " ")
## (ikDollar, "$")
var i = 0
var kind: InterpolatedKind
while true:
var j = i
if j < s.len and s[j] == '$':
if j+1 < s.len and s[j+1] == '{':
inc j, 2
var nesting = 0
block curlies:
while j < s.len:
case s[j]
of '{': inc nesting
of '}':
if nesting == 0:
inc j
break curlies
dec nesting
else: discard
inc j
raise newException(ValueError,
"Expected closing '}': " & substr(s, i, s.high))
inc i, 2 # skip ${
kind = ikExpr
elif j+1 < s.len and s[j+1] in IdentStartChars:
inc j, 2
while j < s.len and s[j] in IdentChars: inc(j)
inc i # skip $
kind = ikVar
elif j+1 < s.len and s[j+1] == '$':
inc j, 2
inc i # skip $
kind = ikDollar
else:
raise newException(ValueError,
"Unable to parse a varible name at " & substr(s, i, s.high))
else:
while j < s.len and s[j] != '$': inc j
kind = ikStr
if j > i:
# do not copy the trailing } for ikExpr:
yield (kind, substr(s, i, j-1-ord(kind == ikExpr)))
else:
break
i = j
when isMainModule:
import sequtils
let input = "$test{} $this is ${an{ example}} "
let expected = @[(ikVar, "test"), (ikStr, "{} "), (ikVar, "this"),
(ikStr, " is "), (ikExpr, "an{ example}"), (ikStr, " ")]
doAssert toSeq(interpolatedFragments(input)) == expected
var value = 0
discard parseHex("0x38", value)
doAssert value == 56
discard parseHex("0x34", value)
doAssert value == 56 * 256 + 52
value = -1
discard parseHex("0x38", value)
doAssert value == -200
value = -1
doAssert(parseSaturatedNatural("848", value) == 3)
doAssert value == 848
value = -1
discard parseSaturatedNatural("84899999999999999999324234243143142342135435342532453", value)
doAssert value == high(int)
value = -1
discard parseSaturatedNatural("9223372036854775808", value)
doAssert value == high(int)
value = -1
discard parseSaturatedNatural("9223372036854775807", value)
doAssert value == high(int)
value = -1
discard parseSaturatedNatural("18446744073709551616", value)
doAssert value == high(int)
value = -1
discard parseSaturatedNatural("18446744073709551615", value)
doAssert value == high(int)
value = -1
doAssert(parseSaturatedNatural("1_000_000", value) == 9)
doAssert value == 1_000_000
{.pop.}