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; }'