feat: String.Slice.toInt? (#11358)

This PR adds `String.Slice.toInt?` and variants.

Closes #11275.
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Markus Himmel 2025-11-25 16:48:41 +01:00 committed by GitHub
parent d99c515b16
commit 85d7f3321c
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4 changed files with 151 additions and 90 deletions

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@ -13,7 +13,6 @@ public import Init.Data.String.Defs
public import Init.Data.String.Extra
public import Init.Data.String.Iterator
public import Init.Data.String.Lemmas
public import Init.Data.String.Repr
public import Init.Data.String.Bootstrap
public import Init.Data.String.Slice
public import Init.Data.String.Pattern

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@ -1,89 +0,0 @@
/-
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura, Mario Carneiro
-/
module
prelude
public import Init.Data.String.Substring
import Init.Data.String.Search
public section
/--
Interprets a string as the decimal representation of an integer, returning it. Returns `none` if
the string does not contain a decimal integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally `-` in front. Leading `+` characters are not allowed.
Use `String.isInt` to check whether `String.toInt?` would return `some`. `String.toInt!` is an
alternative that panics instead of returning `none` when the string is not an integer.
Examples:
* `"".toInt? = none`
* `"-".toInt? = none`
* `"0".toInt? = some 0`
* `"5".toInt? = some 5`
* `"-5".toInt? = some (-5)`
* `"587".toInt? = some 587`
* `"-587".toInt? = some (-587)`
* `" 5".toInt? = none`
* `"2-3".toInt? = none`
* `"0xff".toInt? = none`
-/
def String.toInt? (s : String) : Option Int := do
if s.front = '-' then do
let v ← (s.toRawSubstring.drop 1).toNat?;
pure <| - Int.ofNat v
else
Int.ofNat <$> s.toNat?
/--
Checks whether the string can be interpreted as the decimal representation of an integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally `-` in front. Leading `+` characters are not allowed.
Use `String.toInt?` or `String.toInt!` to convert such a string to an integer.
Examples:
* `"".isInt = false`
* `"-".isInt = false`
* `"0".isInt = true`
* `"-0".isInt = true`
* `"5".isInt = true`
* `"587".isInt = true`
* `"-587".isInt = true`
* `"+587".isInt = false`
* `" 5".isInt = false`
* `"2-3".isInt = false`
* `"0xff".isInt = false`
-/
def String.isInt (s : String) : Bool :=
if s.front = '-' then
(s.toRawSubstring.drop 1).isNat
else
s.isNat
/--
Interprets a string as the decimal representation of an integer, returning it. Panics if the string
does not contain a decimal integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally `-` in front. Leading `+` characters are not allowed.
Use `String.isInt` to check whether `String.toInt!` would return a value. `String.toInt?` is a safer
alternative that returns `none` instead of panicking when the string is not an integer.
Examples:
* `"0".toInt! = 0`
* `"5".toInt! = 5`
* `"587".toInt! = 587`
* `"-587".toInt! = -587`
-/
def String.toInt! (s : String) : Int :=
match s.toInt? with
| some v => v
| none => panic "Int expected"

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@ -420,6 +420,78 @@ Examples:
@[inline] def toNat! (s : String) : Nat :=
s.toSlice.toNat!
/--
Interprets a string as the decimal representation of an integer, returning it. Returns {lean}`none`
if the string does not contain a decimal integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally {lit}`-` in front. Leading `+` characters are not allowed.
Use {name (scope := "Init.Data.String.Search")}`String.isInt` to check whether {name}`String.toInt?`
would return {lean}`some`. {name (scope := "Init.Data.String.Search")}`String.toInt!` is an
alternative that panics instead of returning {lean}`none` when the string is not an integer.
Examples:
* {lean}`"".toInt? = none`
* {lean}`"-".toInt? = none`
* {lean}`"0".toInt? = some 0`
* {lean}`"5".toInt? = some 5`
* {lean}`"-5".toInt? = some (-5)`
* {lean}`"587".toInt? = some 587`
* {lean}`"-587".toInt? = some (-587)`
* {lean}`" 5".toInt? = none`
* {lean}`"2-3".toInt? = none`
* {lean}`"0xff".toInt? = none`
-/
@[inline] def toInt? (s : String) : Option Int :=
s.toSlice.toInt?
/--
Checks whether the string can be interpreted as the decimal representation of an integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally {lit}`-` in front. Leading `+` characters are not allowed.
Use {name}`String.toInt?` or {name (scope := "Init.Data.String.Search")}`String.toInt!` to convert
such a string to an integer.
Examples:
* {lean}`"".isInt = false`
* {lean}`"-".isInt = false`
* {lean}`"0".isInt = true`
* {lean}`"-0".isInt = true`
* {lean}`"5".isInt = true`
* {lean}`"587".isInt = true`
* {lean}`"-587".isInt = true`
* {lean}`"+587".isInt = false`
* {lean}`" 5".isInt = false`
* {lean}`"2-3".isInt = false`
* {lean}`"0xff".isInt = false`
-/
@[inline] def isInt (s : String) : Bool :=
s.toSlice.isInt
/--
Interprets a string as the decimal representation of an integer, returning it. Panics if the string
does not contain a decimal integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally {lit}`-` in front. Leading `+` characters are not allowed.
Use {name}`String.isInt` to check whether {name}`String.toInt!` would return a value.
{name}`String.toInt?` is a safer alternative that returns {lean}`none` instead of panicking when the
string is not an integer.
Examples:
* {lean}`"0".toInt! = 0`
* {lean}`"5".toInt! = 5`
* {lean}`"587".toInt! = 587`
* {lean}`"-587".toInt! = -587`
-/
@[inline] def toInt! (s : String) : Int :=
s.toSlice.toInt!
/--
Returns the first character in {name}`s`. If {name}`s` is empty, returns {name}`none`.

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@ -1339,6 +1339,85 @@ Examples:
def front (s : Slice) : Char :=
s.front?.getD default
/--
Checks whether the slice can be interpreted as the decimal representation of an integer.
A slice can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally {lit}`-` in front. Leading {lit}`+` characters are not allowed.
Use {name (scope := "Init.Data.String.Slice")}`String.Slice.toInt?` or {name (scope := "Init.Data.String.Slice")}`String.toInt!` to convert such a string to an integer.
Examples:
* {lean}`"".toSlice.isInt = false`
* {lean}`"-".toSlice.isInt = false`
* {lean}`"0".toSlice.isInt = true`
* {lean}`"-0".toSlice.isInt = true`
* {lean}`"5".toSlice.isInt = true`
* {lean}`"587".toSlice.isInt = true`
* {lean}`"-587".toSlice.isInt = true`
* {lean}`"+587".toSlice.isInt = false`
* {lean}`" 5".toSlice.isInt = false`
* {lean}`"2-3".toSlice.isInt = false`
* {lean}`"0xff".toSlice.isInt = false`
-/
def isInt (s : Slice) : Bool :=
if s.front = '-' then
(s.drop 1).isNat
else
s.isNat
/--
Interprets a slice as the decimal representation of an integer, returning it. Returns {lean}`none` if
the string does not contain a decimal integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally {lit}`-` in front. Leading {lit}`+` characters are not allowed.
Use {name}`Slice.isInt` to check whether {name}`Slice.toInt?` would return {lean}`some`.
{name (scope := "Init.Data.String.Slice")}`Slice.toInt!` is an alternative that panics instead of
returning {lean}`none` when the string is not an integer.
Examples:
* {lean}`"".toSlice.toInt? = none`
* {lean}`"-".toSlice.toInt? = none`
* {lean}`"0".toSlice.toInt? = some 0`
* {lean}`"5".toSlice.toInt? = some 5`
* {lean}`"-5".toSlice.toInt? = some (-5)`
* {lean}`"587".toSlice.toInt? = some 587`
* {lean}`"-587".toSlice.toInt? = some (-587)`
* {lean}`" 5".toSlice.toInt? = none`
* {lean}`"2-3".toSlice.toInt? = none`
* {lean}`"0xff".toSlice.toInt? = none`
-/
def toInt? (s : Slice) : Option Int :=
if s.front = '-' then
Int.negOfNat <$> (s.drop 1).toNat?
else
Int.ofNat <$> s.toNat?
/--
Interprets a string as the decimal representation of an integer, returning it. Panics if the string
does not contain a decimal integer.
A string can be interpreted as a decimal integer if it only consists of at least one decimal digit
and optionally {lit}`-` in front. Leading `+` characters are not allowed.
Use {name}`Slice.isInt` to check whether {name}`Slice.toInt!` would return a value.
{name}`Slice.toInt?` is a safer alternative that returns {lean}`none` instead of panicking when the
string is not an integer.
Examples:
* {lean}`"0".toSlice.toInt! = 0`
* {lean}`"5".toSlice.toInt! = 5`
* {lean}`"587".toSlice.toInt! = 587`
* {lean}`"-587".toSlice.toInt! = -587`
-/
@[inline]
def toInt! (s : Slice) : Int :=
match s.toInt? with
| some v => v
| none => panic "Int expected"
/--
Returns the last character in {name}`s`. If {name}`s` is empty, returns {name}`none`.