Scala DSL to easily compose awk programs. Its underlying goal is to serve as a simple and concise example of how to build DSLs upon Scala.
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
src
.gitignore
LICENSE
README.md
build.sbt

README.md

ScalAwk

Scala DSL to easily compose awk programs. Its underlying goal is to serve as a simple and concise example of how to build DSLs upon Scala.

Features

It targets a subset of awk by which you can build commands with:

  • Customized separators.
  • Actions executed before iterating over the input lines.
  • Actions for each line.
  • Actions after the input has been exhausted.

These actions can be composed of one or several:

  • Variable assignments.
  • Arithmetic operations: +, -, *, /
  • String concatenations.
  • Prints to standard output.

Examples

Count lines:

lines provided('s := 0) computing ('s := 's + 1) finallyDo (present('s))
> awk 'BEGIN{s = 0; }{s = s + 1; }END{print s; }'

Concatenation with custom split element

lines splitBy ";" arePresentedAs ('c1, 'c2)
> awk -F ';' '{print $1 $2; }'

or:

lines splitBy ";" computing ('concatenated := 'c1 ++ 'c2) arePresentedAs ('concatenated)
> awk -F ';' '{concatenated = $1  $2; print concatenated; }'

Regular expressions as token separators

lines splitBy "_+".r arePresentedAs ('c1, " ", 'c2, "hello", 1, 'x)
> awk -F '_+' '{print $1 " " $2 "hello" 1 x; }'

Other examples

lines splitBy "_+".r arePresentedAs ('c1, " ", 'c2, "hello", 1, 'x)
> awk -F '_+' '{print $1 " " $2 "hello" 1 x; }'

lines computing ('x := 4, 's := 2, 'res := 'x * ('s + 1)) arePresentedAs ('res)
> awk '{x = 4; s = 2; res = x * (s + 1); print res; }'