Os

Background

Given a file named "pen.json" with:

{
  "type": "application",
  "dependencies": {
    "Os": "pen:///os",
    "Core": "pen:///core"
  }
}

Build an application

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  File'Write(ctx, File'StdOut(), "Hello, world!")?

  none
}

When I successfully run pen build

Then I successfully run ./app

And the stdout from "./app" should contain exactly "Hello, world!".

Get arguments

Given a file named "main.pen" with:

import Core'String
import Os'Context { Context }
import Os'Environment
import Os'File
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  File'Write(ctx, File'StdOut(), String'Join(Environment'Arguments(ctx), " "))?

  none
}

When I successfully run pen build

Then I successfully run ./app foo bar

And stdout from "./app foo bar" should contain exactly "foo bar".

Get an environment variable

Given a file named "main.pen" with:

import Core'String
import Os'Context { Context }
import Os'File
import Os'Environment
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  File'Write(ctx, File'StdOut(), Environment'Variable(ctx, "FOO")?)?

  none
}

And I append "foo" to the environment variable "FOO"

When I successfully run pen build

Then I successfully run ./app

And stdout from "./app" should contain exactly "foo".

Open a file

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File { File }
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  File'Open(ctx, "./foo.txt")?

  none
}

And a file named "foo.txt" with ""

When I successfully run pen build

Then I successfully run ./app.

Read a file

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'File'OpenOptions
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  f = File'Open(ctx, "foo.txt")?
  d = File'Read(ctx, f)?

  File'Write(ctx, File'StdOut(), d)?

  none
}

And a file named "foo.txt" with "foo"

When I successfully run pen build

Then I successfully run ./app

And the stdout from "./app" should contain exactly "foo".

Read a file until a limit

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  f = File'Open(ctx, "foo.txt")?
  d = File'ReadLimit(ctx, f, 5)?
  File'Write(ctx, File'StdOut(), d)?

  none
}

And a file named "foo.txt" with "Hello, world!"

When I successfully run pen build

Then I successfully run ./app

And the stdout from "./app" should contain exactly "Hello".

Write a file

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'File'OpenOptions { OpenOptions }
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  f = File'OpenWithOptions(
    ctx,
    "./foo.txt",
    OpenOptions{...OpenOptions'Default(), Write: true},
  )?

  File'Write(ctx, f, "foo")?

  none
}

And a file named "foo.txt" with ""

When I successfully run pen build

Then I successfully run ./app

And the file "foo.txt" should contain "foo".

Copy a file

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'Process

main = \(ctx context) none {
  if _ = File'Copy(ctx.Os, "foo.txt", "bar.txt") as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

And a file named "foo.txt" with "foo"

When I successfully run pen build

Then I successfully run ./app

And the file "foo.txt" should contain "foo"

And the file "bar.txt" should contain "foo".

Move a file

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'Process

main = \(ctx context) none {
  if _ = File'Move(ctx.Os, "foo.txt", "bar.txt") as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

And a file named "foo.txt" with "foo"

When I successfully run pen build

Then I successfully run ./app

And the file "foo.txt" does not exist

And the file "bar.txt" should contain "foo".

Remove a file

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'Process

main = \(ctx context) none {
  if _ = File'Remove(ctx.Os, "foo.txt") as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

And a file named "foo.txt" with ""

When I successfully run pen build

Then I successfully run ./app

And the file "foo.txt" does not exist.

Read a directory

Given a file named "main.pen" with:

import Core'String
import Os'Context { Context }
import Os'File
import Os'Directory
import Os'Process

main = \(ctx context) none {
  if _ = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  File'Write(
    ctx,
    File'StdOut(),
    String'Join(Directory'Read(ctx, ".")?, "\n"),
  )?

  none
}

When I successfully run pen build

Then I successfully run ./app

And the stdout from "./app" should contain "main.pen"

And the stdout from "./app" should contain "pen.json".

Create a directory

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'Directory
import Os'Process

main = \(ctx context) none {
  if _ = Directory'Create(ctx.Os, "foo") as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

When I successfully run pen build

Then I successfully run ./app

And a directory named "foo" should exist.

Remove a directory

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'Directory
import Os'Process

main = \(ctx context) none {
  if _ = Directory'Remove(ctx.Os, "foo") as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

And a directory named "foo"

When I successfully run pen build

Then I successfully run ./app

And a directory named "foo" should not exist.

Get file metadata

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'File
import Os'File'Metadata { Metadata }
import Os'Process

main = \(ctx context) none {
  m = File'Metadata(ctx.Os, "foo")

  c = if m = m as Metadata {
    if m.Size == 3 {
      0
    } else {
      1
    }
  } else {
    1
  }

  Process'Exit(ctx.Os, c)
}

And a file named "foo" with:

foo

When I successfully run pen build

Then I successfully run ./app.

Get system time

Given a file named "main.pen" with:

import Core'Number
import Os'Context { Context }
import Os'File
import Os'Process
import Os'Time

main = \(ctx context) none {
  if m = run(ctx.Os) as none {
    none
  } else {
    Process'Exit(ctx.Os, 1)
  }
}

run = \(ctx Context) none | error {
  File'Write(ctx, File'StdOut(), Number'String(Time'Now(ctx)))?

  none
}

When I successfully run pen build

Then I successfully run ./app.

Sleep

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'Time

main = \(ctx context) none {
  Time'Sleep(ctx.Os, 1)
}

When I successfully run pen build

Then I successfully run ./app.

Exit a process

Given a file named "main.pen" with:

import Os'Context { Context }
import Os'Process

main = \(ctx context) none {
  Process'Exit(ctx.Os, 42)
}

When I successfully run pen build

Then I run ./app

And the exit status should be 42.