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    <p>While Scalas syntax is powerful, it is not flexible enough to create arbitrary delimiters for symbols. Thus, there is no way to leave commas and replace them only with spaces.</p> <p>Nevertheless, it is possible to use macros and parse a string with arbitrary content at compile time. It is not an "easy" solution, but one that works:</p> <pre><code>object AlgDefDSL { import language.experimental.macros import scala.reflect.macros.Context implicit class DefDSL(sc: StringContext) { def dsl(): Definition = macro __dsl_impl } def __dsl_impl(c: Context)(): c.Expr[Definition] = { import c.universe._ val defn = c.prefix.tree match { case Apply(_, List(Apply(_, List(Literal(Constant(s: String)))))) =&gt; def toAST[A : TypeTag](xs: Tree*): Tree = Apply( Select(Ident(typeOf[A].typeSymbol.companionSymbol), newTermName("apply")), xs.toList ) def toVarAST(varObj: Var) = toAST[Var](c.literal(varObj.name).tree) def toEqAST(eqObj: Eq) = toAST[Eq]((eqObj.head +: eqObj.body).map(toVarAST(_)): _*) def toDefAST(defObj: Definition) = toAST[Definition](c.literal(defObj.name).tree +: defObj.body.map(toEqAST(_)): _*) parsers.parse(s) match { case parsers.Success(defn, _) =&gt; toDefAST(defn) case parsers.NoSuccess(msg, _) =&gt; c.abort(c.enclosingPosition, msg) } } c.Expr(defn) } import scala.util.parsing.combinator.JavaTokenParsers private object parsers extends JavaTokenParsers { override val whiteSpace = "[ \t]*".r lazy val newlines = opt(rep("\n")) lazy val varP = "[a-z]+".r ^^ Var lazy val eqP = (varP &lt;~ "=") ~ rep(varP) ^^ { case lhs ~ rhs =&gt; Eq(lhs, rhs: _*) } lazy val defHead = newlines ~&gt; ("[a-zA-Z]+".r &lt;~ "{") &lt;~ newlines lazy val defBody = rep(eqP &lt;~ rep("\n")) lazy val defEnd = "}" ~ newlines lazy val defP = defHead ~ defBody &lt;~ defEnd ^^ { case name ~ eqs =&gt; Definition(name, eqs: _*) } def parse(s: String) = parseAll(defP, s) } case class Var(name: String) case class Eq(head: Var, body: Var*) case class Definition(name: String, body: Eq*) } </code></pre> <p>It can be used with something like this:</p> <pre><code>scala&gt; import AlgDefDSL._ import AlgDefDSL._ scala&gt; dsl""" | Dummy { | x = y z | y = x z | } | """ res12: AlgDefDSL.Definition = Definition(Dummy,WrappedArray(Eq(Var(x),WrappedArray(Var(y), Var(z))), Eq(Var(y),WrappedArray(Var(x), Var(z))))) </code></pre>
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    1. POInternal DSL in Scala: Lists without ","
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    1. USkiritsuku
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    1. COThanks for your answer. Parsing and creating an external DSL is not what I'm currently looking for. I was looking for a way to make my internal DSL look more like what I had in mind. If it's not really possible, then it's OK. I hit the limitations of Scala for creating internal DSLs.
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    2. COBut this answer is still awesome. Much more valuable than the original question. I would share this as much as i can.
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    3. CO@Odomontois well, I appreciate his answer and it's certainly useful, but it's not what I'm looking for.
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