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@olafurpg

olafurpg/PrettyPrintHack.scala

Last active March 3, 2016 12:38
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Pretty-print/reformat AST trees in Scala using clang-format
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PrettyPrintHack.scala
ollie-scalafmt@ import scala.sys.process._
import scala.sys.process._
ollie-scalafmt@ import java.io.ByteArrayInputStream
import java.io.ByteArrayInputStream
ollie-scalafmt@ formatMe
res28: String = """
Defn.Object(Nil, Term.Name("State"), Template(Nil, Seq(Ctor.Ref.Name("ScalaFmtLogger")), Term.Param(Nil, Name.Anonymous(), None, None), Some(Seq(Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("start"))), None, Term.Apply(Term.Name("State"), Seq(Lit(0), Term.Name("identity"), Term.ApplyType(Term.Select(Term.Name("Vector"), Term.Name("empty")), Seq(Type.Name("Split"))), Term.ApplyType(Term.Select(Term.Name("Vector"), Term.Name("empty")), Seq(Type.Name("State"))), Lit(0), Term.ApplyType(Term.Select(Term.Name("Vector"), Term.Name("empty")), Seq(Type.Apply(Type.Name("Indent"), Seq(Type.Name("Num"))))), Lit(0)))), Defn.Def(Nil, Term.Name("reconstructPath"), Nil, Seq(Seq(Term.Param(Nil, Term.Name("toks"), Some(Type.Apply(Type.Name("Array"), Seq(Type.Name("FormatToken")))), None), Term.Param(Nil, Term.Name("splits"), Some(Type.Apply(Type.Name("Vector"), Seq(Type.Name("Split")))), None), Term.Param(Nil, Term.Name("style"), Some(Type.Name("ScalaStyle")), None), Term.Param(Nil, Term.Name("debug"), Some(Type.Name("Boolean")), Some(Lit(false))))), Some(Type.Apply(Type.Name("Seq"), Seq(Type.Tuple(Seq(Type.Name("FormatToken"), Type.Name("String")))))), Term.Block(Seq(Defn.Var(Nil, Seq(Pat.Var.Term(Term.Name("state"))), None, Some(Term.Select(Term.Name("State"), Term.Name("start")))), Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("result"))), None, Term.Apply(Term.Select(Term.Apply(Term.Select(Term.Name("toks"), Term.Name("zip")), Seq(Term.Name("splits"))), Term.Name("map")), Seq(Term.PartialFunction(Seq(Case(Pat.Tuple(Seq(Pat.Var.Term(Term.Name("tok")), Pat.Var.Term(Term.Name("split")))), None, Term.Block(Seq(Term.If(Term.Name("debug"), Term.Block(Seq(Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("left"))), None, Term.Apply(Term.Name("small"), Seq(Term.Select(Term.Name("tok"), Term.Name("left"))))), Term.Apply(Term.Select(Term.Name("logger"), Term.Name("debug")), Seq(Term.Interpolate(Term.Name("f"), Seq(Lit(""), Lit("%-10s "), Lit("")), Seq(Term.Name("left"), Term.Name("split"))))))), Lit()), Term.Assign(Term.Name("state"), Term.Apply(Term.Select(Term.Name("state"), Term.Name("next")), Seq(Term.Name("style"), Term.Name("split"), Term.Name("tok")))), Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("whitespace"))), None, Term.Match(Term.Select(Term.Name("split"), Term.Name("modification")), Seq(Case(Term.Name("Space"), None, Lit(" ")), Case(Pat.Typed(Pat.Var.Term(Term.Name("nl")), Type.Name("NewlineT")), None, Term.Block(Seq(Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("newline"))), None, Term.If(Term.Select(Term.Name("nl"), Term.Name("isDouble")), Lit("\n\n"), Lit("\n"))), Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("indentation"))), None, Term.If(Term.Select(Term.Name("nl"), Term.Name("noIndent")), Lit(""), Term.ApplyInfix(Lit(" "), Term.Name("*"), Nil, Seq(Term.Select(Term.Name("state"), Term.Name("indentation")))))), Term.ApplyInfix(Term.Name("newline"), Term.Name("+"), Nil, Seq(Term.Name("indentation")))))), Case(Pat.Extract(Term.Name("Provided"), Nil, Seq(Pat.Var.Term(Term.Name("literal")))), None, Term.Name("literal")), Case(Term.Name("NoSplit"), None, Lit(""))))), Term.ApplyInfix(Term.Name("tok"), Term.Name("->"), Nil, Seq(Term.Name("whitespace"))))))))))), Term.If(Term.Name("debug"), Term.Apply(Term.Select(Term.Name("logger"), Term.Name("debug")), Seq(Term.Interpolate(Term.Name("s"), Seq(Lit("Total cost: "), Lit("")), Seq(Term.Select(Term.Name("state"), Term.Name("cost")))))), Lit()), Term.Name("result"))))))))
ollie-scalafmt@ (List("clang-format", "-style={ContinuationIndentWidth: 2, ColumnLimit: 120}") #< new ByteArrayInputStream(formatMe.getBytes("UTF-8"))).!!.trim
res29: String = """
Defn.Object(
Nil, Term.Name("State"),
Template(
Nil, Seq(Ctor.Ref.Name("ScalaFmtLogger")), Term.Param(Nil, Name.Anonymous(), None, None),
Some(Seq(
Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("start"))), None,
Term.Apply(
Term.Name("State"),
Seq(Lit(0), Term.Name("identity"),
Term.ApplyType(Term.Select(Term.Name("Vector"), Term.Name("empty")), Seq(Type.Name("Split"))),
Term.ApplyType(Term.Select(Term.Name("Vector"), Term.Name("empty")), Seq(Type.Name("State"))),
Lit(0), Term.ApplyType(Term.Select(Term.Name("Vector"), Term.Name("empty")),
Seq(Type.Apply(Type.Name("Indent"), Seq(Type.Name("Num"))))),
Lit(0)))),
Defn.Def(
Nil, Term.Name("reconstructPath"), Nil,
Seq(Seq(
Term.Param(Nil, Term.Name("toks"), Some(Type.Apply(Type.Name("Array"), Seq(Type.Name("FormatToken")))), None),
Term.Param(Nil, Term.Name("splits"), Some(Type.Apply(Type.Name("Vector"), Seq(Type.Name("Split")))), None),
Term.Param(Nil, Term.Name("style"), Some(Type.Name("ScalaStyle")), None),
Term.Param(Nil, Term.Name("debug"), Some(Type.Name("Boolean")), Some(Lit(false))))),
Some(Type.Apply(Type.Name("Seq"), Seq(Type.Tuple(Seq(Type.Name("FormatToken"), Type.Name("String")))))),
Term.Block(Seq(
Defn.Var(Nil, Seq(Pat.Var.Term(Term.Name("state"))), None,
Some(Term.Select(Term.Name("State"), Term.Name("start")))),
Defn.Val(
Nil, Seq(Pat.Var.Term(Term.Name("result"))), None,
Term.Apply(
Term.Select(Term.Apply(Term.Select(Term.Name("toks"), Term.Name("zip")), Seq(Term.Name("splits"))),
Term.Name("map")),
Seq(Term.PartialFunction(Seq(Case(
Pat.Tuple(Seq(Pat.Var.Term(Term.Name("tok")), Pat.Var.Term(Term.Name("split")))), None,
Term.Block(Seq(
Term.If(Term.Name("debug"),
Term.Block(Seq(
Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("left"))), None,
Term.Apply(Term.Name("small"),
Seq(Term.Select(Term.Name("tok"), Term.Name("left"))))),
Term.Apply(Term.Select(Term.Name("logger"), Term.Name("debug")),
Seq(Term.Interpolate(Term.Name("f"), Seq(Lit(""), Lit("%-10s "), Lit("")),
Seq(Term.Name("left"), Term.Name("split"))))))),
Lit()),
Term.Assign(Term.Name("state"),
Term.Apply(Term.Select(Term.Name("state"), Term.Name("next")),
Seq(Term.Name("style"), Term.Name("split"), Term.Name("tok")))),
Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("whitespace"))), None,
Term.Match(
Term.Select(Term.Name("split"), Term.Name("modification")),
Seq(Case(Term.Name("Space"), None, Lit(" ")),
Case(Pat.Typed(Pat.Var.Term(Term.Name("nl")), Type.Name("NewlineT")), None,
Term.Block(Seq(
Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("newline"))), None,
Term.If(Term.Select(Term.Name("nl"), Term.Name("isDouble")),
Lit("\n\n"), Lit("\n"))),
Defn.Val(Nil, Seq(Pat.Var.Term(Term.Name("indentation"))), None,
Term.If(Term.Select(Term.Name("nl"), Term.Name("noIndent")), Lit(""),
Term.ApplyInfix(Lit(" "), Term.Name("*"), Nil,
Seq(Term.Select(Term.Name("state"),
Term.Name("indentation")))))),
Term.ApplyInfix(Term.Name("newline"), Term.Name("+"), Nil,
Seq(Term.Name("indentation")))))),
Case(Pat.Extract(Term.Name("Provided"), Nil, Seq(Pat.Var.Term(Term.Name("literal")))),
None, Term.Name("literal")),
Case(Term.Name("NoSplit"), None, Lit(""))))),
Term.ApplyInfix(Term.Name("tok"), Term.Name("->"), Nil, Seq(Term.Name("whitespace"))))))))))),
Term.If(Term.Name("debug"),
Term.Apply(Term.Select(Term.Name("logger"), Term.Name("debug")),
Seq(Term.Interpolate(Term.Name("s"), Seq(Lit("Total cost: "), Lit("")),
Seq(Term.Select(Term.Name("state"), Term.Name("cost")))))),
Lit()),
Term.Name("result"))))))))
"""
@olafurpg
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Author

Assuming you have clang-format installed and in PATH.

@jvican
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jvican commented Feb 16, 2016

Thanks! Just a recommendation: update the title so that it's easier to find this gem when looking it up on Google. Something like "Pretty print AST trees scala" should work.

@olafurpg
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olafurpg commented Mar 3, 2016

Good idea @jvican, updated title!

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