lean4-htt/src/Init/System/FilePath.lean
2021-05-28 14:19:59 +02:00

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/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura, Sebastian Ullrich
-/
prelude
import Init.System.Platform
import Init.Data.String.Basic
import Init.Data.Repr
import Init.Data.ToString.Basic
namespace System
open Platform
structure FilePath where
toString : String
deriving Inhabited, DecidableEq
instance : Repr FilePath where
reprPrec p := Repr.addAppParen ("FilePath.mk " ++ repr p.toString)
instance : ToString FilePath where
toString p := p.toString
namespace FilePath
/-- The character that separates directories. In the case where more than one character is possible, `pathSeparator` is the 'ideal' one. -/
def pathSeparator : Char :=
if isWindows then '\\' else '/'
/-- The list of all possible separators. -/
def pathSeparators : List Char :=
if isWindows then ['\\', '/'] else ['/']
/-- File extension character -/
def extSeparator : Char := '.'
def exeExtension : String :=
if isWindows then "exe" else ""
/-- Case-insensitive file system -/
def isCaseInsensitive : Bool := isWindows || isOSX
-- TODO: normalize `a/`, `a//b`, etc.
def normalize (p : FilePath) (normalizeCase := isCaseInsensitive) : FilePath :=
if pathSeparators.length == 1 && !normalizeCase then p
else ⟨p.toString.map fun c =>
if pathSeparators.contains c then pathSeparator
else if normalizeCase then c.toLower
else c⟩
-- the following functions follow the names and semantics from Rust's `std::path::Path`
def isAbsolute (p : FilePath) : Bool :=
pathSeparators.contains p.toString.front || (isWindows && p.toString.bsize >= 1 && p.toString[1] == ':')
def isRelative (p : FilePath) : Bool :=
!p.isAbsolute
def join (p sub : FilePath) : FilePath :=
if sub.isAbsolute then
sub
else
⟨p.toString ++ pathSeparator.toString ++ sub.toString⟩
instance : Div FilePath where
div := FilePath.join
instance : HDiv FilePath String FilePath where
hDiv p sub := FilePath.join p ⟨sub⟩
private def posOfLastSep (p : FilePath) : Option String.Pos :=
p.toString.revFind pathSeparators.contains
def parent (p : FilePath) : Option FilePath :=
FilePath.mk <$> p.toString.extract 0 <$> posOfLastSep p
def fileName (p : FilePath) : Option String :=
let lastPart := match posOfLastSep p with
| some sepPos => p.toString.extract (sepPos + 1) p.toString.bsize
| none => p.toString
if lastPart.isEmpty || lastPart == "." || lastPart == ".." then none else some lastPart
/-- Extracts the stem (non-extension) part of `p.fileName`. -/
def fileStem (p : FilePath) : Option String :=
p.fileName.map fun fname =>
match fname.revPosOf '.' with
| some 0 => fname
| some pos => fname.extract 0 pos
| none => fname
def extension (p : FilePath) : Option String :=
p.fileName.bind fun fname =>
match fname.revPosOf '.' with
| some 0 => none
| some pos => fname.extract (pos + 1) fname.bsize
| none => none
def withFileName (p : FilePath) (fname : String) : FilePath :=
match p.parent with
| none => ⟨fname⟩
| some p => p / fname
def withExtension (p : FilePath) (ext : String) : FilePath :=
match p.fileStem with
| none => p
| some stem => p.withFileName (if ext.isEmpty then stem else stem ++ "." ++ ext)
def components (p : FilePath) : List String :=
p.normalize (normalizeCase := false) |>.toString.splitOn pathSeparator.toString
end FilePath
def mkFilePath (parts : List String) : FilePath :=
⟨String.intercalate FilePath.pathSeparator.toString parts⟩
abbrev SearchPath := List FilePath
namespace SearchPath
/-- The character that is used to separate the entries in the $PATH (or %PATH%) environment variable. -/
protected def separator : Char :=
if isWindows then ';' else ':'
def parse (s : String) : SearchPath :=
s.split (fun c => SearchPath.separator == c) |>.map FilePath.mk
def toString (path : SearchPath) : String :=
SearchPath.separator.toString.intercalate (path.map FilePath.toString)
end SearchPath
end System