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#
#
# Nim's Runtime Library
# (c) Copyright 2016 Joey Payne
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module contains various string utility routines that are uncommonly
## used in comparison to `strutils <strutils.html>`_.
import strutils
{.deadCodeElim: on.} # dce option deprecated
proc expandTabs*(s: string, tabSize: int = 8): string {.noSideEffect,
procvar.} =
## Expand tab characters in `s` replacing them by spaces.
##
## The amount of inserted spaces for each tab character is the difference
## between the current column number and the next tab position. Tab positions
## occur every `tabSize` characters.
## The column number starts at 0 and is increased with every single character
## and inserted space, except for newline, which resets the column number
## back to 0.
runnableExamples:
doAssert expandTabs("\t", 4) == " "
doAssert expandTabs("\tfoo\t", 4) == " foo "
doAssert expandTabs("\tfoo\tbar", 4) == " foo bar"
doAssert expandTabs("\tfoo\tbar\t", 4) == " foo bar "
doAssert expandTabs("ab\tcd\n\txy\t", 3) == "ab cd\n xy "
result = newStringOfCap(s.len + s.len shr 2)
var pos = 0
template addSpaces(n) =
for j in 0 ..< n:
result.add(' ')
pos += 1
for i in 0 ..< len(s):
let c = s[i]
if c == '\t':
let
denominator = if tabSize > 0: tabSize else: 1
numSpaces = tabSize - pos mod denominator
addSpaces(numSpaces)
else:
result.add(c)
pos += 1
if c == '\l':
pos = 0
proc partition*(s: string, sep: string,
right: bool = false): (string, string, string)
{.noSideEffect, procvar.} =
## Split the string at the first or last occurrence of `sep` into a 3-tuple
##
## Returns a 3 string tuple of (beforeSep, `sep`, afterSep) or
## (`s`, "", "") if `sep` is not found and `right` is false or
## ("", "", `s`) if `sep` is not found and `right` is true
runnableExamples:
doAssert partition("foo:bar", ":") == ("foo", ":", "bar")
doAssert partition("foobarbar", "bar") == ("foo", "bar", "bar")
doAssert partition("foobarbar", "bank") == ("foobarbar", "", "")
doAssert partition("foobarbar", "foo") == ("", "foo", "barbar")
doAssert partition("foofoobar", "bar") == ("foofoo", "bar", "")
let position = if right: s.rfind(sep) else: s.find(sep)
if position != -1:
return (s[0 ..< position], sep, s[position + sep.len ..< s.len])
return if right: ("", "", s) else: (s, "", "")
proc rpartition*(s: string, sep: string): (string, string, string)
{.noSideEffect, procvar.} =
## Split the string at the last occurrence of `sep` into a 3-tuple
##
## Returns a 3 string tuple of (beforeSep, `sep`, afterSep) or
## ("", "", `s`) if `sep` is not found
runnableExamples:
doAssert rpartition("foo:bar", ":") == ("foo", ":", "bar")
doAssert rpartition("foobarbar", "bar") == ("foobar", "bar", "")
doAssert rpartition("foobarbar", "bank") == ("", "", "foobarbar")
doAssert rpartition("foobarbar", "foo") == ("", "foo", "barbar")
doAssert rpartition("foofoobar", "bar") == ("foofoo", "bar", "")
return partition(s, sep, right = true)
when isMainModule:
doAssert expandTabs("\t", 4) == " "
doAssert expandTabs("\tfoo\t", 4) == " foo "
doAssert expandTabs("\tfoo\tbar", 4) == " foo bar"
doAssert expandTabs("\tfoo\tbar\t", 4) == " foo bar "
doAssert expandTabs("", 4) == ""
doAssert expandTabs("", 0) == ""
doAssert expandTabs("\t\t\t", 0) == ""
doAssert partition("foo:bar", ":") == ("foo", ":", "bar")
doAssert partition("foobarbar", "bar") == ("foo", "bar", "bar")
doAssert partition("foobarbar", "bank") == ("foobarbar", "", "")
doAssert partition("foobarbar", "foo") == ("", "foo", "barbar")
doAssert partition("foofoobar", "bar") == ("foofoo", "bar", "")
doAssert rpartition("foo:bar", ":") == ("foo", ":", "bar")
doAssert rpartition("foobarbar", "bar") == ("foobar", "bar", "")
doAssert rpartition("foobarbar", "bank") == ("", "", "foobarbar")
doAssert rpartition("foobarbar", "foo") == ("", "foo", "barbar")
doAssert rpartition("foofoobar", "bar") == ("foofoo", "bar", "")
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