psst-hs

PaSteboard String Tranform tool - Haskell edition.

There are two ways to get data into this tool, cat something to it, or just run it and it will take the value in your pasteboard.

There are a lot of tools for transforming strings on the CLI, but the most useful tool is the one you remember how to use. This tool aims to be useful, but unsurprising in behavior.

Concepts

• This utility transforms strings with a typed dsl.
• The syntax is inspired by Julialang's pipeline operator |>
• This utility was born as a reimplentation of daniel-beard/psst with the following:
  • Less syntax (for now), 'command' based
  • Better documentation
  • A typed representation
  • Fast start time (Julia takes a while to warm up)
  • Easy to add new commands
  • Better error messages
  • Interpreted, with ability to output partial results in case of errors

Examples

echo 'hello world' | psst-hs 'words |> uppercase |> take(2) |> base64 |> unbase64'
["HE","WO"]

Types and Examples

There are currently only a few types in psst-hs:

- VString
- VStringList
- VInt
- VBool
- VError

Many commands work the same across VString and VStringList types. The function used in the VString type is just mapped across the list.

Commands

Commands are chained by the pipeline operator |>. Each command opts in to a particular input type.

VString

base64 -> VString

• Description: Base64 encoding of a VString
• Example:

echo 'hello world' | psst-hs 'base64'
> aGVsbG8gd29ybGQK

head -> VString

• Description: Take the first value
• Example:

echo 'hello world' | psst-hs 'head'
> h

length -> VInt

• Description: Return a VInt representing the length of a VString
• Example:

echo 'hi' | psst-hs 'length'
> 2

lowercase -> VString

• Description: Return a VString with all characters set to lowercase
• Example:

echo 'HELLO WORLD' | psst-hs 'lowercase'
> "hello world"

match -> VStringList

• Description: Return all matches for a given regex
• Example:

echo 'hello world' | psst-hs 'match("[a-z]+")'
["hello", "world"]

matches -> VBool

• Description: Return a VBool indicating if input matches a regex
• Example:

echo "hello world" | psst-hs 'matches("\\w+")'
True

reverse -> VStringList

• Description: Return a VString with the characters reversed from their original order
• Example:

echo 'hello world' | psst-hs 'reverse'
> dlrow olleh

tail -> VString

• Description: All characters except the first one. Returns a VString
• Example:

echo 'hello world' | psst-hs 'tail'
> ello world

take(Int) -> VString

• Description: Output only the prefix number of characters. Returns a VString
• Example:

echo 'hello world' | psst-hs 'take(4)'
> hell

unbase64 -> VString

• Description: Decode a base64 representation. Returns a VString.
• Example:

echo 'aGVsbG8gd29ybGQK' | psst-hs 'unbase64'
> hello world

uppercase -> VString

• Description: Uppercase the string. Returns a VString
• Example:

echo 'hello world' | psst-hs 'uppercase'
> HELLO WORLD

words -> VStringList

• Description: Split a VString into components separated by whitespace. Returns a VStringList
• Example:

echo 'hello world' | psst-hs 'words'
> ["hello", "world"]

---

VStringList

base64 -> VStringList

• Description: Maps the VString method across a VStringList
• Example:

echo 'hello world' | psst-hs 'words |> base64'
> ["aGVsbG8=","d29ybGQ="]

length -> VInt

• Description: Returns the length of the VStringList as VInt
• Example:

echo 'hello world' | psst-hs 'words |> length'
> 2

lowercase -> VStringList

• Description: Maps the VString method across a VStringList
• Example:

echo 'HELLO WORLD' | psst-hs 'words |> lowercase'
> ["hello", "world"]

reverse -> VStringList

• Description: Reverse the order of elements within the VStringList
• Example:

echo 'hello world' | psst-hs 'words |> reverse'
> ["world", "hello"]

unbase64 -> VStringList

• Description: Maps the VString method across a VStringList
• Example:

echo 'aGVsbG8= d29ybGQ=' | psst-hs 'words |> unbase64'
> ["hello", "world"]

uppercase -> VStringList

• Description: Maps the VString method across a VStringList
• Example:

echo 'hello world' | psst-hs 'words |> uppercase'
> ["HELLO", "WORLD"]

tail -> VString

• Description: Returns the last VString from a VStringList
• Example:

echo 'hello world' | psst-hs 'words |> tail'
> ["WORLD"]

take(VInt) -> VStringList

• Description: Returns the first n VString values from a VStringList
• Example:

echo '1 2 3 4 5' | psst-hs 'words |> take(4)'
> ["1", "2", "3", "4"]

---

Building on macOS

brew install pcre

# For M1s
brew list pcre | grep 'pcre\.h$'

/opt/homebrew/include

ln -s /usr/local/pcre-8.45 /usr/sbin/pcre
ln -s /usr/local/pcre-8.45/include/pcre.h /usr/include/pcre.h