stdlib_system: essential path functionality (#999)

Author: perazz

doc/specs/stdlib_system.md

@@ -174,7 +174,7 @@ The result is a real value representing the elapsed time in seconds, measured fr
 
 ### Syntax
 
-`delta_t = ` [[stdlib_system(module):elapsed(subroutine)]] `(process)`
+`delta_t = ` [[stdlib_system(module):elapsed(interface)]] `(process)`
 
 ### Arguments
 
@@ -212,7 +212,7 @@ in case of process hang or delay.
 
 ### Syntax
 
-`call ` [[stdlib_system(module):wait(subroutine)]] `(process [, max_wait_time])`
+`call ` [[stdlib_system(module):wait(interface)]] `(process [, max_wait_time])`
 
 ### Arguments
 
@@ -243,7 +243,7 @@ This is especially useful for monitoring asynchronous processes and retrieving t
 
 ### Syntax
 
-`call ` [[stdlib_system(module):update(subroutine)]] `(process)`
+`call ` [[stdlib_system(module):update(interface)]] `(process)`
 
 ### Arguments
 
@@ -269,7 +269,7 @@ This interface is useful when a process needs to be forcefully stopped, for exam
 
 ### Syntax
 
-`call ` [[stdlib_system(module):kill(subroutine)]] `(process, success)`
+`call ` [[stdlib_system(module):kill(interface)]] `(process, success)`
 
 ### Arguments
 
@@ -298,7 +298,7 @@ It ensures that the requested sleep duration is honored on both Windows and Unix
 
 ### Syntax
 
-`call ` [[stdlib_system(module):sleep(subroutine)]] `(millisec)`
+`call ` [[stdlib_system(module):sleep(interface)]] `(millisec)`
 
 ### Arguments
 
@@ -324,7 +324,7 @@ This function is highly efficient and works during the compilation phase, avoidi
 
 ### Syntax
 
-`result = ` [[stdlib_system(module):is_windows(function)]] `()`
+`result = ` [[stdlib_system(module):is_windows(interface)]] `()`
 
 ### Return Value
 
@@ -359,7 +359,7 @@ If the OS cannot be identified, the function returns `OS_UNKNOWN`.
 
 ### Syntax
 
-`os = [[stdlib_system(module):get_runtime_os(function)]]()`
+`os = ` [[stdlib_system(module):get_runtime_os(function)]] `()`
 
 ### Class
 
@@ -396,7 +396,7 @@ This caching mechanism ensures negligible overhead for repeated calls, unlike `g
 
 ### Syntax
 
-`os = [[stdlib_system(module):OS_TYPE(function)]]()`
+`os = ` [[stdlib_system(module):OS_TYPE(function)]]`()`
 
 ### Class
 
@@ -431,7 +431,7 @@ It is designed to work across multiple platforms. On Windows, paths with both fo
 
 ### Syntax
 
-`result = [[stdlib_system(module):is_directory(function)]] (path)`
+`result = ` [[stdlib_system(module):is_directory(function)]]`(path)`
 
 ### Class
 
@@ -471,7 +471,7 @@ It reads as an empty file. The null device's path varies by operating system:
 
 ### Syntax
 
-`path = [[stdlib_system(module):null_device(function)]]()`
+`path = ` [[stdlib_system(module):null_device(function)]]`()`
 
 ### Class
 
@@ -506,7 +506,7 @@ The function provides an optional error-handling mechanism via the `state_type`
 
 ### Syntax
 
-`call [[stdlib_system(module):delete_file(subroutine)]] (path [, err])`
+`call ` [[stdlib_system(module):delete_file(subroutine)]]` (path [, err])`
 
 ### Class
 Subroutine
@@ -532,3 +532,175 @@ The file is removed from the filesystem if the operation is successful. If the o
 ```fortran
 {!example/system/example_delete_file.f90!}
 ```
+
+## `join_path` - Joins the provided paths according to the OS
+
+### Status
+
+Experimental
+
+### Description
+
+This interface joins the paths provided to it according to the platform specific path-separator.
+i.e `\` for windows and `/` for others
+
+### Syntax
+
+`res = ` [[stdlib_system(module):join_path(interface)]] ` (p1, p2)`
+
+`res = ` [[stdlib_system(module):join_path(interface)]] ` (p)`
+
+### Class
+Pure function
+
+### Arguments
+
+`p1, p2`: Shall be a character string or `type(string_type)`. It is an `intent(in)` argument.
+    or
+`p`: Shall be a list of character strings or list of `type(string_type)`. It is an `intent(in)` argument.
+
+### Return values
+
+The resultant path, either a character string or `type(string_type)`.
+
+## `operator(/)`
+
+Alternative syntax to`join_path` using an overloaded operator. Join two paths according to the platform specific path-separator.
+
+### Status
+
+Experimental
+
+### Syntax
+
+`p = lval / rval`
+
+### Class
+
+Pure function.
+
+### Arguments
+
+`lval`: A character string or `type(string_type)`. It is an `intent(in)` argument.
+
+`rval`: A character string or `type(string_type)`. It is an `intent(in)` argument.
+
+### Result value
+
+The result is an `allocatable` character string or `type(string_type)`
+
+#### Example
+
+```fortran
+{!example/system/example_path_join.f90!}
+```
+
+## `split_path` - splits a path immediately following the last separator
+
+### Status
+
+Experimental
+
+### Description
+
+This subroutine splits a path immediately following the last separator after removing the trailing separators
+splitting it into most of the times a directory and a file name.
+
+### Syntax
+
+`call `[[stdlib_system(module):split_path(interface)]]`(p, head, tail)`
+
+### Class
+Subroutine
+
+### Arguments
+
+`p`: A character string or `type(string_type)` containing the path to be split. It is an `intent(in)` argument.
+`head`: The first part of the path. Either a character string or `type(string_type)`. It is an `intent(out)` argument.
+`tail`: The rest part of the path. Either a character string or `type(string_type)`. It is an `intent(out)` argument.
+
+### Behavior
+
+- If `p` is empty, `head` is set to `.` and `tail` is left empty.
+- If `p` consists entirely of path-separators, `head` is set to the path-separator and `tail` is left empty.
+- `head` ends with a path-separator if and only if `p` appears to be a root directory or child of one.
+
+### Return values
+
+The splitted path. `head` and `tail`.
+
+### Example
+
+```fortran
+{!example/system/example_path_split_path.f90!}
+```
+
+## `base_name` - The last part of a path
+
+### Status
+
+Experimental
+
+### Description
+
+This function returns the last part of a path after removing trailing path separators.
+
+### Syntax
+
+`res = ` [[stdlib_system(module):base_name(interface)]]`(p)`
+
+### Class
+Function
+
+### Arguments
+
+`p`: the path, a character string or `type(string_type)`. It is an `intent(in)` argument.
+
+### Behavior
+
+- The `tail` of `[[stdlib_system(module):split_path(interface)]]` is exactly what is returned. Same Behavior.
+
+### Return values
+
+A character string or `type(string_type)`.
+
+### Example
+
+```fortran
+{!example/system/example_path_base_name.f90!}
+```
+
+## `dir_name` - Everything except the last part of the path
+
+### Status
+
+Experimental
+
+### Description
+
+This function returns everything except the last part of a path.
+
+### Syntax
+
+`res = ` [[stdlib_system(module):dir_name(interface)]]`(p)`
+
+### Class
+Function
+
+### Arguments
+
+`p`: the path, a character string or `type(string_type)`. It is an `intent(in)` argument.
+
+### Behavior
+
+- The `head` of `[[stdlib_system(module):split_path(interface)]]` is exactly what is returned. Same Behavior.
+
+### Return values
+
+A character string or `type(string_type)`.
+
+### Example
+
+```fortran
+{!example/system/example_path_dir_name.f90!}
+```

example/system/CMakeLists.txt

@@ -11,3 +11,7 @@ ADD_EXAMPLE(process_5)
 ADD_EXAMPLE(process_6)
 ADD_EXAMPLE(process_7)
 ADD_EXAMPLE(sleep)
+ADD_EXAMPLE(path_join)
+ADD_EXAMPLE(path_split_path)
+ADD_EXAMPLE(path_base_name)
+ADD_EXAMPLE(path_dir_name)

example/system/example_path_base_name.f90

@@ -0,0 +1,16 @@
+! Usage of base_name
+program example_path_base_name
+    use stdlib_system, only: base_name, OS_TYPE, OS_WINDOWS
+    character(len=:), allocatable :: p1
+
+    if(OS_TYPE() == OS_WINDOWS) then
+        p1 = 'C:\Users'
+    else
+        p1 = '/home'
+    endif 
+    
+    print *, 'base name of '// p1 // ' -> ' // base_name(p1) 
+    ! base name of C:\Users -> Users
+    ! OR
+    ! base name of /home -> home
+end program example_path_base_name

example/system/example_path_dir_name.f90

@@ -0,0 +1,16 @@
+! Usage of dir_name
+program example_path_dir_name
+    use stdlib_system, only: dir_name, OS_TYPE, OS_WINDOWS
+    character(len=:), allocatable :: p1, head, tail
+
+    if(OS_TYPE() == OS_WINDOWS) then
+        p1 = 'C:\Users' ! C:\Users
+    else
+        p1 = '/home' ! /home
+    endif 
+
+    print *, 'dir_name of '// p1 // ' -> ' // dir_name(p1) 
+    ! dir_name of C:\Users -> C:\
+    ! OR
+    ! dir_name of /home -> /
+end program example_path_dir_name

example/system/example_path_join.f90

@@ -0,0 +1,23 @@
+! Usage of join_path, operator(/)
+program example_path_join
+    use stdlib_system, only: join_path, operator(/), OS_TYPE, OS_WINDOWS
+    character(len=:), allocatable :: p1, p2, p3
+    character(len=20) :: parr(4)
+
+    if(OS_TYPE() == OS_WINDOWS) then
+        p1 = 'C:'/'Users'/'User1'/'Desktop'
+        p2 = join_path('C:\Users\User1', 'Desktop')
+        parr = [character(len=20) :: 'C:', 'Users', 'User1', 'Desktop']
+        p3 = join_path(parr)
+    else
+        p1 = ''/'home'/'User1'/'Desktop'
+        p2 = join_path('/home/User1', 'Desktop')
+        parr = [character(len=20) :: '', 'home', 'User1', 'Desktop']
+        p3 = join_path(parr)
+    end if
+
+    ! (p1 == p2 == p3) = '/home/User1/Desktop' OR 'C:\Users\User1\Desktop'
+    print *, p1 ! /home/User1/Desktop OR 'C:\Users\User1\Desktop'
+    print *, "p1 == p2: ", p1 == p2 ! T
+    print *, "p2 == p3: ", p2 == p3 ! T
+end program example_path_join

example/system/example_path_split_path.f90

@@ -0,0 +1,25 @@
+! Usage of split_path
+program example_path_split_path
+    use stdlib_system, only: join_path, split_path, OS_TYPE, OS_WINDOWS
+    character(len=:), allocatable :: p1, head, tail
+
+    if(OS_TYPE() == OS_WINDOWS) then
+        p1 = join_path('C:\Users\User1', 'Desktop') ! C:\Users\User1\Desktop
+    else
+        p1 = join_path('/home/User1', 'Desktop') ! /home/User1/Desktop
+    endif 
+    
+    call split_path(p1, head, tail)
+    ! head = /home/User1 OR C:\Users\User1, tail = Desktop
+    print *, p1 // " -> " // head // " + " // tail 
+    ! C:\Users\User1\Desktop -> C:\Users\User1 + Desktop
+    ! OR
+    ! /home/User1/Desktop -> /home/User1 + Desktop
+
+    call split_path(head, p1, tail)
+    ! p1 = /home OR C:\Users, tail = User1
+    print *, head // " -> " // p1 // " + " // tail 
+    ! C:\Users\User1 -> C:\Users + User1
+    ! OR
+    ! /home/User1 -> /home + User1
+end program example_path_split_path

src/CMakeLists.txt

@@ -93,7 +93,6 @@ set(fppFiles
 # Preprocessed files to contain preprocessor directives -> .F90
 set(cppFiles
     stdlib_linalg_constants.fypp
-
     stdlib_linalg_blas.fypp
     stdlib_linalg_lapack.fypp
 )
@@ -118,6 +117,7 @@ set(SRC
     stdlib_sorting_radix_sort.f90
     stdlib_system_subprocess.c
     stdlib_system_subprocess.F90
+    stdlib_system_path.f90
     stdlib_system.F90
     stdlib_sparse.f90
     stdlib_specialfunctions_legendre.f90