object ImportViral {
def apply( packagespec:PS ):ImportViral =
new ImportViral( packagespec )
}
class ImportViral( packagespec:PS ) extends ImportStatement( packagespec ) {}
And my respective rule in the parser:
def ZImportViral = rule { "importviral" ~ WhiteSpace ~ ZPS ~~> ast.ImportViral }
But this resulted in a rather ugly error:
error: overloaded method value ~~> with alternatives: [X, Y, Z, R](f: (X, Y, Z, ast.PS) => R)org.parboiled.scala.rules.ReductionRule3[X,Y,Z,R] and [Y, Z, R](f: (Y, Z, ast.PS) => R)org.parboiled.scala.rules.ReductionRule2[Y,Z,R] and [Z, R](f: (Z, ast.PS) => R)org.parboiled.scala.rules.ReductionRule1[Z,R] and [R](f: ast.PS => R)org.parboiled.scala.rules.Rule1[R] cannot be applied to (net.codingwell.weave.languages.silk.ast.ImportViral.type)
I figured out pretty quick that the issue was f: ast.PS => R meaning it wanted some sort of conversion from my PackageSpecification to "R" (ImportViral). So obviously I did something wrong. I fiddled for half the day before trying hardcoding the rule type.
def ZImportViral:Rule1[ast.ImportViral]
This gave me a new only minorly more helpful error.
found : net.codingwell.weave.languages.silk.ast.ImportViral.type (with underlying type object net.codingwell.weave.languages.silk.ast.ImportViral) required: net.codingwell.weave.languages.silk.ast.PackageSpecification => net.codingwell.weave.languages.silk.ast.ImportViral
So again, my object isn't a conversion. After another several hour sprint trying to figure out what a case class is equivalent to in code. I found a decompiler http://java.decompiler.free.fr/?q=preview
Plugged in a case class from my AST and looked for differences. Took me a little bit to notice but plain as day, the object was inheriting from Function1. The magical glue to make a function object in scala. Now I am no Scala expert so this also taught me that objects can inherit from different things than their companion class. Who Knew?
Final working code:
object ImportViral extends Function1[PS,ImportViral] {
def apply( packagespec:PS ):ImportViral = new ImportViral( packagespec )
}
class ImportViral( packagespec:PS ) extends ImportStatement( packagespec ) {}
This code can be found on github: Github - Deathbobomega/Weave - ast.scala
