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Improve the ropes module (#17145)

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* Improve ropes module

Improve wording
Update runnableExamples
Add index bound check for `[]`
Minor format changes

* Update tests/stdlib/tropes.nim

Run on C & JS target
Test in VM
Add tests for `[]`
This commit is contained in:
konsumlamm
2021-02-22 19:58:37 +01:00
committed by GitHub
parent d76d79336f
commit a1f4113705
2 changed files with 130 additions and 117 deletions
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110
lib/pure/ropes.nim
View File

@@ -8,7 +8,7 @@
#
## This module contains support for a `rope`:idx: data type.
## Ropes can represent very long strings efficiently; especially concatenation
## Ropes can represent very long strings efficiently; in particular, concatenation
## is done in O(1) instead of O(n). They are essentially concatenation
## trees that are only flattened when converting to a native Nim
## string. The empty string is represented by `nil`. Ropes are immutable and
@@ -16,8 +16,8 @@
## Leaves can be cached for better memory efficiency at the cost of
## runtime efficiency.
include "system/inclrtl"
import streams
include system/inclrtl
import std/streams
{.push debugger: off.} # the user does not want to trace a part
# of the standard library!
@@ -29,8 +29,8 @@ var
cacheEnabled = false
type
Rope* = ref RopeObj ## empty rope is represented by nil
RopeObj {.acyclic.} = object
Rope* {.acyclic.} = ref object
## A rope data type. The empty rope is represented by `nil`.
left, right: Rope
length: int
data: string # not empty if a leaf
@@ -45,8 +45,7 @@ type
proc len*(a: Rope): int {.rtl, extern: "nro$1".} =
## The rope's length.
if a == nil: result = 0
else: result = a.length
if a == nil: 0 else: a.length
proc newRope(): Rope = new(result)
proc newRope(data: string): Rope =
@@ -128,8 +127,9 @@ proc insertInCache(s: string, tree: Rope): Rope =
proc rope*(s: string = ""): Rope {.rtl, extern: "nro$1Str".} =
## Converts a string to a rope.
runnableExamples:
var r = rope("I'm a rope")
let r = rope("I'm a rope")
doAssert $r == "I'm a rope"
if s.len == 0:
result = nil
else:
@@ -146,15 +146,17 @@ proc rope*(s: string = ""): Rope {.rtl, extern: "nro$1Str".} =
proc rope*(i: BiggestInt): Rope {.rtl, extern: "nro$1BiggestInt".} =
## Converts an int to a rope.
runnableExamples:
var r = rope(429)
let r = rope(429)
doAssert $r == "429"
result = rope($i)
proc rope*(f: BiggestFloat): Rope {.rtl, extern: "nro$1BiggestFloat".} =
## Converts a float to a rope.
runnableExamples:
var r = rope(4.29)
let r = rope(4.29)
doAssert $r == "4.29"
result = rope($f)
proc enableCache*() {.rtl, extern: "nro$1".} =
@@ -170,12 +172,9 @@ proc disableCache*() {.rtl, extern: "nro$1".} =
proc `&`*(a, b: Rope): Rope {.rtl, extern: "nroConcRopeRope".} =
## The concatenation operator for ropes.
runnableExamples:
var
r1 = rope("Hello, ")
r2 = rope("Nim!")
let r = r1 & r2
let r = rope("Hello, ") & rope("Nim!")
doAssert $r == "Hello, Nim!"
if a == nil:
result = b
elif b == nil:
@@ -189,78 +188,62 @@ proc `&`*(a, b: Rope): Rope {.rtl, extern: "nroConcRopeRope".} =
proc `&`*(a: Rope, b: string): Rope {.rtl, extern: "nroConcRopeStr".} =
## The concatenation operator for ropes.
runnableExamples:
var
r1 = rope("Hello, ")
r2 = "Nim!"
let r = r1 & r2
let r = rope("Hello, ") & "Nim!"
doAssert $r == "Hello, Nim!"
result = a & rope(b)
proc `&`*(a: string, b: Rope): Rope {.rtl, extern: "nroConcStrRope".} =
## The concatenation operator for ropes.
runnableExamples:
var
r1 = "Hello, "
r2 = rope("Nim!")
let r = r1 & r2
let r = "Hello, " & rope("Nim!")
doAssert $r == "Hello, Nim!"
result = rope(a) & b
proc `&`*(a: openArray[Rope]): Rope {.rtl, extern: "nroConcOpenArray".} =
## The concatenation operator for an openarray of ropes.
## The concatenation operator for an `openArray` of ropes.
runnableExamples:
let s = @[rope("Hello, "), rope("Nim"), rope("!")]
let r = &s
let r = &[rope("Hello, "), rope("Nim"), rope("!")]
doAssert $r == "Hello, Nim!"
for item in a: result = result & item
proc add*(a: var Rope, b: Rope) {.rtl, extern: "nro$1Rope".} =
## Adds `b` to the rope `a`.
runnableExamples:
var
r1 = rope("Hello, ")
r2 = rope("Nim!")
var r = rope("Hello, ")
r.add(rope("Nim!"))
doAssert $r == "Hello, Nim!"
r1.add(r2)
doAssert $r1 == "Hello, Nim!"
a = a & b
proc add*(a: var Rope, b: string) {.rtl, extern: "nro$1Str".} =
## Adds `b` to the rope `a`.
runnableExamples:
var
r1 = rope("Hello, ")
r2 = "Nim!"
var r = rope("Hello, ")
r.add("Nim!")
doAssert $r == "Hello, Nim!"
r1.add(r2)
doAssert $r1 == "Hello, Nim!"
a = a & b
proc `[]`*(r: Rope, i: int): char {.rtl, extern: "nroCharAt".} =
## Returns the character at position `i` in the rope `r`. This is quite
## expensive! Worst-case: O(n). If `i >= r.len`, `\0` is returned.
## expensive! Worst-case: O(n). If `i >= r.len or i < 0`, `\0` is returned.
runnableExamples:
let r1 = rope("Hello, Nim!")
let r = rope("Hello, Nim!")
doAssert r1[0] == 'H'
doAssert r1[7] == 'N'
doAssert r1[22] == '\0'
let r2 = rope("Hello") & rope(", Nim!")
doAssert r2[0] == 'H'
doAssert r2[7] == 'N'
doAssert r2[22] == '\0'
doAssert r[0] == 'H'
doAssert r[7] == 'N'
doAssert r[22] == '\0'
var x = r
var j = i
if x == nil: return
if x == nil or i < 0 or i >= r.len: return
while true:
if x != nil and x.data.len > 0:
if j < x.data.len: return x.data[j]
return '\0'
# leaf
return x.data[j]
else:
if x.left.length > j:
x = x.left
@@ -276,7 +259,7 @@ iterator leaves*(r: Rope): string =
var index = 0
for leave in r.leaves:
doAssert leave == s[index]
inc index
inc(index)
if r != nil:
var stack = @[r]
@@ -307,8 +290,7 @@ proc `$`*(r: Rope): string {.rtl, extern: "nroToString".} =
result = newStringOfCap(r.len)
for s in leaves(r): add(result, s)
proc `%`*(frmt: string, args: openArray[Rope]): Rope {.
rtl, extern: "nroFormat".} =
proc `%`*(frmt: string, args: openArray[Rope]): Rope {.rtl, extern: "nroFormat".} =
## `%` substitution operator for ropes. Does not support the `$identifier`
## nor `${identifier}` notations.
runnableExamples:
@@ -317,6 +299,10 @@ proc `%`*(frmt: string, args: openArray[Rope]): Rope {.
let r2 = "$# $# $#" % [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r2 == "Nim is a great language"
let r3 = "${1} ${2} ${3}" % [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r3 == "Nim is a great language"
var i = 0
var length = len(frmt)
result = nil
@@ -357,13 +343,13 @@ proc `%`*(frmt: string, args: openArray[Rope]): Rope {.
if i - 1 >= start:
add(result, substr(frmt, start, i - 1))
proc addf*(c: var Rope, frmt: string, args: openArray[Rope]) {.
rtl, extern: "nro$1".} =
proc addf*(c: var Rope, frmt: string, args: openArray[Rope]) {.rtl, extern: "nro$1".} =
## Shortcut for `add(c, frmt % args)`.
runnableExamples:
var r = rope("Dash: ")
r.addf "$1 $2 $3", [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r == "Dash: Nim is a great language"
add(c, frmt % args)
when not defined(js) and not defined(nimscript):
@@ -386,14 +372,12 @@ when not defined(js) and not defined(nimscript):
bpos = 0
blen = readBuffer(f, addr(buf[0]), buf.len)
if blen == 0: # no more data in file
result = false
return
return false
let n = min(blen - bpos, slen - spos)
# TODO There's gotta be a better way of comparing here...
# TODO: There's gotta be a better way of comparing here...
if not equalMem(addr(buf[bpos]),
cast[pointer](cast[int](cstring(s))+spos), n):
result = false
return
cast[pointer](cast[int](cstring(s)) + spos), n):
return false
spos += n
bpos += n

137
tests/stdlib/tropes.nim
View File

@@ -1,73 +1,102 @@
import ropes
discard """
targets: "c js"
"""
import std/ropes
block:
let r: Rope = nil
doAssert r[0] == '\0'
template main() =
block:
let r: Rope = nil
doAssert r[0] == '\0'
doAssert $r == ""
block:
var
r1 = rope("Hello")
r2 = rope("Nim-Lang")
block:
var
r1 = rope("Hello, ")
r2 = rope("Nim-Lang")
let r = r1 & r2
let s = $r
for i in 0 ..< r.len:
doAssert r[i] == s[i]
let r = r1 & r2
let s = $r
doAssert s == "Hello, Nim-Lang"
for i in 0 ..< r.len:
doAssert r[i] == s[i]
doAssert r[66] == '\0'
doAssert r[66] == '\0'
block:
let r = rope("Hello, Nim-Lang")
block:
let r = rope("Hello, Nim-Lang")
let s = $r
for i in 0 ..< r.len:
doAssert r[i] == s[i]
let s = $r
doAssert s == "Hello, Nim-Lang"
for i in 0 ..< r.len:
doAssert r[i] == s[i]
doAssert r[66] == '\0'
doAssert r[66] == '\0'
block:
var r: Rope
r.add rope("Nim ")
r.add rope("is ")
r.add rope("a ")
r.add rope("great ")
r.add rope("language")
block:
var r: Rope
r.add rope("Nim ")
r.add rope("is ")
r.add rope("a ")
r.add rope("great ")
r.add rope("language")
let s = $r
for i in 0 ..< r.len:
doAssert r[i] == s[i]
let s = $r
doAssert s == "Nim is a great language"
for i in 0 ..< r.len:
doAssert r[i] == s[i]
doAssert r[66] == '\0'
doAssert r[66] == '\0'
block:
var r: Rope
r.add rope("My Conquest")
r.add rope(" is ")
r.add rope("the Sea of Stars")
block:
var r: Rope
r.add rope("My Conquest")
r.add rope(" is ")
r.add rope("the Sea of Stars")
let s = $r
for i in 0 ..< r.len:
doAssert r[i] == s[i]
let s = $r
doAssert s == "My Conquest is the Sea of Stars"
for i in 0 ..< r.len:
doAssert r[i] == s[i]
doAssert r[66] == '\0'
doAssert r[66] == '\0'
block:
var r: Rope
r.add rope("My Conquest")
r.add rope(" is ")
r.add rope("the Sea of Stars")
block:
var r: Rope
r.add rope("My Conquest")
r.add rope(" is ")
r.add rope("the Sea of Stars")
var i: int
for item in r:
doAssert r[i] == item
inc i
doAssert $r == "My Conquest is the Sea of Stars"
doAssert r[66] == '\0'
var i: int
for item in r:
doAssert r[i] == item
inc i
block:
let r1 = "$1 $2 $3" % [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r1 == "Nim is a great language"
doAssert r[66] == '\0'
let r2 = "$# $# $#" % [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r2 == "Nim is a great language"
block:
let r1 = "$1 $2 $3" % [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r1 == "Nim is a great language"
let r2 = "$# $# $#" % [rope("Nim"), rope("is"), rope("a great language")]
doAssert $r2 == "Nim is a great language"
block: # `[]`
let r1 = rope("Hello, Nim!")
doAssert r1[-2] == '\0'
doAssert r1[0] == 'H'
doAssert r1[7] == 'N'
doAssert r1[22] == '\0'
let r2 = rope("Hello") & rope(", Nim!")
doAssert r2[-2] == '\0'
doAssert r2[0] == 'H'
doAssert r2[7] == 'N'
doAssert r2[22] == '\0'
static: main()
main()