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60 jmp (-51) 10
65 halt</pre>
=={{header|Scala}}==
The complete implementation for the compiler tasks can be found in a GitHub repository at [https://github.com/edadma/rosettacodeCompiler github.com/edadma/rosettacodeCompiler] which includes full unit testing for the samples given in [[Compiler/Sample programs]].
The following code implements an interpreter for the output of the [http://rosettacode.org/wiki/Compiler/syntax_analyzer#Scala parser].
<lang scala>
package xyz.hyperreal.rosettacodeCompiler
import scala.collection.mutable.{ArrayBuffer, HashMap}
import scala.io.Source
object CodeGenerator {
def fromStdin = fromSource(Source.stdin)
def fromString(src: String) = fromSource(Source.fromString(src))
def fromSource(ast: Source) = {
val vars = new HashMap[String, Int]
val strings = new ArrayBuffer[String]
val code = new ArrayBuffer[String]
var s: Stream[String] = ast.getLines.toStream
def line =
if (s.nonEmpty) {
val n = s.head
s = s.tail
n.split(" +", 2) match {
case Array(n) => n
case a => a
}
} else
sys.error("unexpected end of AST")
def variableIndex(name: String) =
vars get name match {
case None =>
val idx = vars.size
vars(name) = idx
idx
case Some(idx) => idx
}
def stringIndex(s: String) =
strings indexOf s match {
case -1 =>
val idx = strings.length
strings += s
idx
case idx => idx
}
var loc = 0
def addSimple(inst: String) = {
code += f"$loc%4d $inst"
loc += 1
}
def addOperand(inst: String, operand: String) = {
code += f"$loc%4d $inst%-5s $operand"
loc += 5
}
def fixup(inst: String, idx: Int, at: Int) = code(idx) = f"$at%4d $inst%-5s (${loc - at - 1}) $loc"
generate
addSimple("halt")
println(s"Datasize: ${vars.size} Strings: ${strings.length}")
for (s <- strings)
println(s)
println(code mkString "\n")
def generate: Unit =
line match {
case "Sequence" =>
generate
generate
case ";" =>
case "Assign" =>
val idx =
line match {
case Array("Identifier", name: String) =>
variableIndex(name)
case l => sys.error(s"expected identifier: $l")
}
generate
addOperand("store", s"[$idx]")
case Array("Identifier", name: String) => addOperand("fetch", s"[${variableIndex(name)}]")
case Array("Integer", n: String) => addOperand("push", s"$n")
case Array("String", s: String) => addOperand("push", s"${stringIndex(s)}")
case "If" =>
generate
val cond = loc
val condidx = code.length
addOperand("", "")
s = s.tail
generate
if (s.head == ";") {
s = s.tail
fixup("jz", condidx, cond)
} else {
val jump = loc
val jumpidx = code.length
addOperand("", "")
fixup("jz", condidx, cond)
generate
fixup("jmp", jumpidx, jump)
}
case "While" =>
val start = loc
generate
val cond = loc
val condidx = code.length
addOperand("", "")
generate
addOperand("jmp", s"(${start - loc - 1}) $start")
fixup("jz", condidx, cond)
case op =>
generate
generate
addSimple(
op match {
case "Prti" => "prti"
case "Prts" => "prts"
case "Prtc" => "prtc"
case "Add" => "add"
case "Subtract" => "sub"
case "Multiply" => "mul"
case "Divide" => "div"
case "Mod" => "mod"
case "Less" => "lt"
case "LessEqual" => "le"
case "Greater" => "gt"
case "GreaterEqual" => "ge"
case "Equal" => "eq"
case "NotEqual" => "ne"
case "And" => "and"
case "Or" => "or"
case "Negate" => "neg"
case "Not" => "not"
}
)
}
}
}
</lang>
=={{header|Scheme}}==
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