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package moe.nea.lisp
object CoreBindings {
val def = LispData.externalRawCall("def") { context, callsite, stackFrame, args ->
if (args.size != 2) {
return@externalRawCall stackFrame.reportError("Function define expects exactly two arguments", callsite)
}
val (name, value) = args
if (name !is LispAst.Reference) {
return@externalRawCall stackFrame.reportError("Define expects a name as first argument", name)
}
if (name.label in stackFrame.variables) {
return@externalRawCall stackFrame.reportError("Cannot redefine value in local context", name)
}
return@externalRawCall stackFrame.setValueLocal(name.label, context.resolveValue(stackFrame, value))
}
private fun isTruthy(data: LispData): Boolean? {
if (data == trueValue) return true
if (data == falseValue) return false
return null
}
val trueValue = LispData.Atom("true")
val falseValue = LispData.Atom("false")
val ifFun = LispData.externalRawCall("if") { context, callsite, stackFrame, args ->
if (args.size != 3) {
return@externalRawCall stackFrame.reportError("if requires 3 arguments", callsite)
}
val (cond, ifTrue, ifFalse) = args
val c = isTruthy(context.resolveValue(stackFrame, cond))
if (c == null) {
return@externalRawCall stackFrame.reportError("Non boolean value $c used as condition for if", cond)
}
if (c) {
return@externalRawCall context.resolveValue(stackFrame, ifTrue)
} else {
return@externalRawCall context.resolveValue(stackFrame, ifFalse)
}
}
val pure = LispData.externalCall("pure") { args, reportError ->
return@externalCall args.singleOrNull()?.let { value ->
LispData.externalCall("pure.r") { args, reportError ->
if (args.isNotEmpty())
reportError("Pure function does not expect arguments")
else
value
}
} ?: reportError("Function pure expects exactly one argument")
}
val lambda = LispData.externalRawCall("lambda") { context, callsite, stackFrame, args ->
if (args.size != 2) {
return@externalRawCall stackFrame.reportError("Lambda needs exactly 2 arguments", callsite)
}
val (argumentNames, body) = args
if (argumentNames !is LispAst.Parenthesis) {
return@externalRawCall stackFrame.reportError("Lambda has invalid argument declaration", argumentNames)
}
val argumentNamesString = argumentNames.items.map {
val ref = it as? LispAst.Reference
if (ref == null) {
return@externalRawCall stackFrame.reportError("Lambda has invalid argument declaration", it)
}
ref.label
}
if (body !is LispAst.Parenthesis) {
return@externalRawCall stackFrame.reportError("Lambda has invalid body declaration", body)
}
LispData.createLambda(stackFrame, argumentNamesString, body)
}
val defun = LispData.externalRawCall("defun") { context, callSite, stackFrame, lispAsts ->
if (lispAsts.size != 3) {
return@externalRawCall stackFrame.reportError("Invalid function definition", callSite)
}
val (name, args, body) = lispAsts
if (name !is LispAst.Reference) {
return@externalRawCall stackFrame.reportError("Invalid function definition name", name)
}
if (name.label in stackFrame.variables) {
return@externalRawCall stackFrame.reportError("Cannot redefine function in local context", name)
}
if (args !is LispAst.Parenthesis) {
return@externalRawCall stackFrame.reportError("Invalid function definition arguments", args)
}
val argumentNames = args.items.map {
val ref = it as? LispAst.Reference
?: return@externalRawCall stackFrame.reportError("Invalid function definition argument name", it)
ref.label
}
if (body !is LispAst.Parenthesis) {
return@externalRawCall stackFrame.reportError("Invalid function definition body", body)
}
return@externalRawCall stackFrame.setValueLocal(
name.label,
LispData.createLambda(stackFrame, argumentNames, body, name.label)
)
}
val seq = LispData.externalRawCall("seq") { context, callsite, stackFrame, args ->
var lastResult: LispData? = null
for (arg in args) {
lastResult = context.executeLisp(stackFrame, arg)
}
lastResult ?: stackFrame.reportError("Seq cannot be invoked with 0 argumens", callsite)
}
internal fun stringify(thing: LispData): String {
return when (thing) {
is LispData.Atom -> ":${thing.label}"
is LispData.JavaExecutable -> "<native function ${thing.name}>"
LispData.LispNil -> "nil"
is LispData.LispNode -> thing.node.toSource()
is LispData.LispList -> thing.elements.joinToString(", ", "[", "]") { stringify(it) }
is LispData.LispString -> thing.string
is LispData.LispNumber -> thing.value.toString()
is LispData.LispInterpretedCallable -> "<function ${thing.name ?: "<anonymous>"} ${thing.argNames} ${thing.body.toSource()}>"
}
}
val tostring = LispData.externalCall("tostring") { args, reportError ->
LispData.LispString(args.joinToString(" ") { stringify(it) })
}
val debuglog = LispData.externalRawCall("debuglog") { context, callsite, stackFrame, args ->
OutputCapture.print(
stackFrame,
args.joinToString(" ", postfix = "\n") { stringify(context.resolveValue(stackFrame, it)) })
LispData.LispNil
}
val add = LispData.externalCall("add") { args, reportError ->
if (args.size == 0) {
return@externalCall reportError("Cannot call add without at least 1 argument")
}
LispData.LispNumber(args.fold(0.0) { a, b ->
a + (b as? LispData.LispNumber
?: return@externalCall reportError("Unexpected argument $b, expected number")).value
})
}
val sub = LispData.externalCall("sub") { args, reportError ->
if (args.size == 0) {
return@externalCall reportError("Cannot call sub without at least 1 argument")
}
val c = args.map {
(it as? LispData.LispNumber
?: return@externalCall reportError("Unexpected argument $it, expected number")
).value
}
LispData.LispNumber(c.drop(1).fold(c.first()) { a, b ->
a - b
})
}
val mul = LispData.externalCall("mul") { args, reportError ->
if (args.size == 0) {
return@externalCall reportError("Cannot call mul without at least 1 argument")
}
LispData.LispNumber(args.fold(1.0) { a, b ->
a * (b as? LispData.LispNumber
?: return@externalCall reportError("Unexpected argument $b, expected number")).value
})
}
val eq = LispData.externalCall("eq") { args, reportError ->
if (args.size == 0) {
return@externalCall reportError("Cannot call eq without at least 1 argument")
}
LispData.boolean(!args.zipWithNext().any { it.first != it.second })
}
val div = LispData.externalCall("div") { args, reportError ->
if (args.size == 0) {
return@externalCall reportError("Cannot call div without at least 1 argument")
}
val c = args.map {
(it as? LispData.LispNumber
?: return@externalCall reportError("Unexpected argument $it, expected number")
).value
}
LispData.LispNumber(c.drop(1).fold(c.first()) { a, b ->
a / b
})
}
val less = LispData.externalCall("less") { args, reportError ->
if (args.size != 2) {
return@externalCall reportError("Cannot call less without exactly 2 arguments")
}
val (left, right) = args.map {
(it as? LispData.LispNumber
?: return@externalCall reportError("Unexpected argument $it, expected number")
).value
}
LispData.boolean(left < right)
}
val import = LispData.externalRawCall("import") { context, callsite, stackFrame, args ->
if (args.size != 1) {
return@externalRawCall stackFrame.reportError("import needs at least one argument", callsite)
}
// TODO: aliased / namespaced imports
val moduleName = when (val moduleObject = context.resolveValue(stackFrame, args[0])) {
is LispData.Atom -> moduleObject.label
is LispData.LispString -> moduleObject.string
else -> return@externalRawCall stackFrame.reportError("import needs a string or atom as argument", callsite)
}
context.importModule(moduleName, stackFrame, callsite)
return@externalRawCall LispData.LispNil
}
val reflect = LispData.externalCall("reflect.type") { args, reportError ->
if (args.size != 1) {
return@externalCall reportError("reflect.type can only return the type for one argument")
}
return@externalCall when (args[0]) {
is LispData.Atom -> LispData.Atom("atom")
is LispData.LispExecutable -> LispData.Atom("callable")
is LispData.LispList -> LispData.Atom("list")
LispData.LispNil -> LispData.Atom("nil")
is LispData.LispNode -> LispData.Atom("ast")
is LispData.LispNumber -> LispData.Atom("number")
is LispData.LispString -> LispData.Atom("string")
}
}
fun offerArithmeticTo(bindings: StackFrame) {
bindings.setValueLocal("core.arith.add", add)
bindings.setValueLocal("core.arith.div", div)
bindings.setValueLocal("core.arith.mul", mul)
bindings.setValueLocal("core.arith.sub", sub)
bindings.setValueLocal("core.arith.less", less)
bindings.setValueLocal("core.arith.eq", eq)
}
fun offerAllTo(bindings: StackFrame) {
bindings.setValueLocal("core.if", ifFun)
bindings.setValueLocal("core.nil", LispData.LispNil)
bindings.setValueLocal("core.def", def)
bindings.setValueLocal("core.tostring", tostring)
bindings.setValueLocal("core.pure", pure)
bindings.setValueLocal("core.lambda", lambda)
bindings.setValueLocal("core.defun", defun)
bindings.setValueLocal("core.seq", seq)
bindings.setValueLocal("core.import", import)
bindings.setValueLocal("core.reflect.type", reflect)
bindings.setValueLocal("core.debuglog", debuglog)
offerArithmeticTo(bindings)
}
}
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