From 16d51b71a5a35914f3b7372ad5c6fb884c4394b5 Mon Sep 17 00:00:00 2001
From: Oliver <okennedy@buffalo.edu>
Date: Sun, 2 Jul 2023 17:53:56 -0400
Subject: [PATCH] Initial stab, borrowing stuff from the JITD compiler

---
 .gitignore                                    |   3 +
 astral/src/com/astraldb/Astral.scala          |   9 +
 astral/src/com/astraldb/ast/AST.scala         |  32 ++
 astral/src/com/astraldb/spec/Definition.scala |  10 +
 astral/src/com/astraldb/spec/Expression.scala | 178 +++++++++++
 astral/src/com/astraldb/spec/Field.scala      |  12 +
 .../astraldb/spec/FunctionDefinition.scala    |  36 +++
 astral/src/com/astraldb/spec/Node.scala       |  12 +
 astral/src/com/astraldb/spec/Pattern.scala    | 223 +++++++++++++
 astral/src/com/astraldb/spec/Statement.scala  | 128 ++++++++
 astral/src/com/astraldb/spec/Type.scala       |  37 +++
 .../typecheck/FunctionSignature.scala         |  33 ++
 .../com/astraldb/typecheck/Typechecker.scala  | 295 ++++++++++++++++++
 build.sc                                      |  30 ++
 14 files changed, 1038 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 astral/src/com/astraldb/Astral.scala
 create mode 100644 astral/src/com/astraldb/ast/AST.scala
 create mode 100755 astral/src/com/astraldb/spec/Definition.scala
 create mode 100755 astral/src/com/astraldb/spec/Expression.scala
 create mode 100755 astral/src/com/astraldb/spec/Field.scala
 create mode 100755 astral/src/com/astraldb/spec/FunctionDefinition.scala
 create mode 100755 astral/src/com/astraldb/spec/Node.scala
 create mode 100644 astral/src/com/astraldb/spec/Pattern.scala
 create mode 100755 astral/src/com/astraldb/spec/Statement.scala
 create mode 100755 astral/src/com/astraldb/spec/Type.scala
 create mode 100755 astral/src/com/astraldb/typecheck/FunctionSignature.scala
 create mode 100755 astral/src/com/astraldb/typecheck/Typechecker.scala
 create mode 100644 build.sc

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..db529cd
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.bloop
+.metals
+/out
diff --git a/astral/src/com/astraldb/Astral.scala b/astral/src/com/astraldb/Astral.scala
new file mode 100644
index 0000000..eed1b87
--- /dev/null
+++ b/astral/src/com/astraldb/Astral.scala
@@ -0,0 +1,9 @@
+package com.astraldb
+
+object Astral
+{
+  def main(args: Array[String]): Unit =
+  {
+    println("Hello!")
+  }
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/ast/AST.scala b/astral/src/com/astraldb/ast/AST.scala
new file mode 100644
index 0000000..4f408b2
--- /dev/null
+++ b/astral/src/com/astraldb/ast/AST.scala
@@ -0,0 +1,32 @@
+package com.astraldb.ast
+
+import com.astraldb.spec.Constant
+
+sealed trait AST
+{
+  def children: Seq[AST]
+
+  def find[T](f: AST => Option[T]): Option[T] =
+  {
+    f(this).orElse {
+      children.foldLeft(None:Option[T]){ (ret, child) =>
+        if(ret.isEmpty) { child.find(f) }
+        else { ret }
+      }
+    }
+  }
+}
+
+case class AList(elements: Seq[AST]) extends AST
+{
+  def children: Seq[AST] = elements
+}
+case class ANode(label: String, elements: Seq[AST]) extends AST
+{
+  def children: Seq[AST] = elements
+}
+case class Leaf(value: Constant) extends AST
+{
+  def children: Seq[AST] = Seq.empty
+}
+
diff --git a/astral/src/com/astraldb/spec/Definition.scala b/astral/src/com/astraldb/spec/Definition.scala
new file mode 100755
index 0000000..efb3482
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Definition.scala
@@ -0,0 +1,10 @@
+package com.astraldb.spec;
+
+import com.astraldb.typecheck._
+
+case class Definition(
+  nodes:Seq[Node],
+  // rules:Seq[Rule]
+) {
+}
+
diff --git a/astral/src/com/astraldb/spec/Expression.scala b/astral/src/com/astraldb/spec/Expression.scala
new file mode 100755
index 0000000..beeed3b
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Expression.scala
@@ -0,0 +1,178 @@
+package com.astraldb.spec
+
+
+object CmpTypes extends Enumeration {
+  type T = Value
+  val Eq, Neq, Lt, Lte, Gt, Gte = Value
+
+  def opString(op:T):String = 
+  {
+    op match {
+      case Eq  => "=="
+      case Neq => "!="
+      case Lt  => "<"
+      case Lte => "<="
+      case Gt  => ">"
+      case Gte => ">="
+    }
+  }
+}
+
+object ArithTypes extends Enumeration {
+  type T = Value
+  val Add, Sub, Mul, Div, And, Or = Value
+
+  def opString(op:T):String = 
+  {
+    op match {
+      case Add => "+"
+      case Sub => "-"
+      case Mul => "*"
+      case Div => "/"
+      case And => "&&"
+      case Or  => "||"
+    }
+  }
+}
+
+sealed abstract class Expression
+{
+  def eq(other:Expression)  = Cmp(CmpTypes.Eq,  this, other)
+  def neq(other:Expression) = Cmp(CmpTypes.Neq, this, other)
+  def lt(other:Expression)  = Cmp(CmpTypes.Lt,  this, other)
+  def lte(other:Expression) = Cmp(CmpTypes.Lte, this, other)
+  def gt(other:Expression)  = Cmp(CmpTypes.Gt,  this, other)
+  def gte(other:Expression) = Cmp(CmpTypes.Gte, this, other)
+
+  def and(other:Expression) = 
+  {
+    (this, other) match { 
+      case (BoolConstant(true), _)  => other
+      case (BoolConstant(false), _) => this
+      case (_, BoolConstant(true))  => this
+      case (_, BoolConstant(false)) => other
+      case _ => Arith(ArithTypes.And, this, other)
+    }
+  }
+  def or(other:Expression) = 
+  {
+    (this, other) match { 
+      case (BoolConstant(false), _)  => other
+      case (BoolConstant(true), _) => this
+      case (_, BoolConstant(false))  => this
+      case (_, BoolConstant(true)) => other
+      case _ => Arith(ArithTypes.Or, this, other)
+    }
+  }
+
+  def plus(other:Expression)      = Arith(ArithTypes.Add, this, other)
+  def minus(other:Expression)     = Arith(ArithTypes.Sub, this, other)
+  def times(other:Expression)     = Arith(ArithTypes.Mul, this, other)
+  def dividedBy(other:Expression) = Arith(ArithTypes.Div, this, other)
+
+  def get(field:String) = StructSubscript(this, field)
+  def get(index:Int)    = ArraySubscript(this, index)
+
+  def disassemble: Seq[Expression]
+  def reassemble(in: Seq[Expression]): Expression
+  def rebuild(fn:(Expression => Expression)): Expression = 
+    reassemble(disassemble.map { fn(_) })
+}
+
+sealed abstract class Constant(val t:Type) extends Expression
+{
+  def disassemble = Seq[Expression]()
+  def reassemble(in: Seq[Expression]): Expression = this
+}
+case class IntConstant(i:Integer) extends Constant(TInt())
+{
+  override def toString:String = i.toString
+}
+case class FloatConstant(f:Double) extends Constant(TFloat())
+{
+  override def toString:String = f.toString
+}
+case class BoolConstant(b:Boolean) extends Constant(TBool())
+{
+  override def toString:String = if(b){ "true" } else { "false" }
+}
+
+case class Var(v:String) extends Expression
+{
+  def disassemble = Seq[Expression]()
+  def reassemble(in: Seq[Expression]): Expression = this
+  override def toString = v.toString
+}
+case class Cmp(t: CmpTypes.T, lhs:Expression, rhs:Expression) extends Expression
+{
+  def disassemble = Seq[Expression](lhs, rhs)
+  def reassemble(in: Seq[Expression]): Expression = Cmp(t, in(0), in(1))
+  override def toString = s"($lhs) ${CmpTypes.opString(t)} ($rhs)"
+}
+case class Arith(t: ArithTypes.T, lhs:Expression, rhs:Expression) extends Expression
+{
+  def disassemble = Seq[Expression](lhs, rhs)
+  def reassemble(in: Seq[Expression]): Expression = Arith(t, in(0), in(1))
+  override def toString = s"($lhs) ${ArithTypes.opString(t)} ($rhs)"
+}
+case class FunctionalIfThenElse(condition:Expression, ifTrue:Expression, ifFalse:Expression) extends Expression
+{
+  def disassemble = Seq[Expression](condition, ifTrue, ifFalse)
+  def reassemble(in: Seq[Expression]): Expression = FunctionalIfThenElse(in(0), in(1), in(2))
+  override def toString = s"($condition) ? ($ifTrue) : ($ifFalse)"
+}
+case class ArraySubscript(target:Expression, index:Integer) extends Expression
+{
+  def disassemble = Seq[Expression](target)
+  def reassemble(in: Seq[Expression]): Expression = ArraySubscript(in(0), index)
+  override def toString = s"$target[$index]"
+}
+case class StructSubscript(target:Expression, field:String) extends Expression
+{
+  def disassemble = Seq[Expression](target)
+  def reassemble(in: Seq[Expression]): Expression = StructSubscript(in(0), field)
+  override def toString = s"$target.$field"
+}
+case class NodeSubscript(target:Expression, field:String) extends Expression
+{
+  def disassemble = Seq[Expression](target)
+  def reassemble(in: Seq[Expression]): Expression = NodeSubscript(in(0), field)
+  override def toString = s"$target->$field"
+}
+case class NodeCast(nodeType: String,target:Expression, field:String) extends Expression
+{
+  def disassemble = Seq[Expression](target)
+  def reassemble(in: Seq[Expression]): Expression = NodeSubscript(in(0), field)
+  override def toString = s"($nodeType *)$target->$field"
+}
+case class FunctionCall(name:String, args:Seq[Expression]) extends Expression
+{
+  def disassemble = args
+  def reassemble(in: Seq[Expression]): Expression = FunctionCall(name, in)
+  override def toString = s"$name(${args.mkString(", ")})"
+}
+case class WrapNode(target: Expression) extends Expression
+{
+  def disassemble = Seq(target)
+  def reassemble(in: Seq[Expression]): Expression = WrapNode(in(0))
+  override def toString = s"wrap ${target.toString}"
+}
+case class UnWrapHandle(target: Expression) extends Expression
+{
+  def disassemble = Seq(target)
+  def reassemble(in: Seq[Expression]): Expression = UnWrapHandle(in(0))
+  override def toString = s"unwraphandleref ${target.toString}"
+}
+case class WrapNodeRef(target: Expression) extends Expression
+{
+  def disassemble = Seq(target)
+  def reassemble(in: Seq[Expression]): Expression = WrapNodeRef(in(0))
+  override def toString = s"wrapnoderef ${target.toString}"
+}
+
+case class MakeNode(nodeType: String, fields: Seq[Expression]) extends Expression
+{
+  def disassemble = fields
+  def reassemble(in: Seq[Expression]): Expression = MakeNode(nodeType, in)
+  override def toString = s"allocate ${nodeType}(${fields.mkString(",")})"  
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/spec/Field.scala b/astral/src/com/astraldb/spec/Field.scala
new file mode 100755
index 0000000..40252bd
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Field.scala
@@ -0,0 +1,12 @@
+package com.astraldb.spec
+
+import scala.language.implicitConversions
+
+case class Field(name:String, t:Type)
+{
+  override def toString = s"$name:${Type.toString(t)}"
+}
+
+object FieldConversions {
+  implicit def tuple2Field(t:(String, Type)): Field = Field(t._1, t._2)
+}
diff --git a/astral/src/com/astraldb/spec/FunctionDefinition.scala b/astral/src/com/astraldb/spec/FunctionDefinition.scala
new file mode 100755
index 0000000..2127e24
--- /dev/null
+++ b/astral/src/com/astraldb/spec/FunctionDefinition.scala
@@ -0,0 +1,36 @@
+package com.astraldb.spec
+
+import com.astraldb.typecheck.FunctionSignature
+
+object FunctionArgType extends Enumeration 
+{
+  type T = Value
+  val Input, OutputRef, ConstInputRef = Value
+
+  def isConst(t: T): Boolean = 
+    t match { 
+      case ConstInputRef => true
+      case Input | OutputRef => false
+    }
+  def isByRef(t: T): Boolean = 
+    t match { 
+      case ConstInputRef | OutputRef => true
+      case Input => false
+    }
+}
+
+case class FunctionDefinition(
+    name: String, 
+    ret: Option[Type], 
+    args: Seq[(String, Type, FunctionArgType.T)], 
+    body: Statement
+) 
+{
+  def signature =
+    ret match { 
+      case Some(t) =>
+        FunctionSignature(name, args.map { _._2 }, t)
+      case None => 
+        FunctionSignature(name, args.map { _._2 })
+    }
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/spec/Node.scala b/astral/src/com/astraldb/spec/Node.scala
new file mode 100755
index 0000000..fc32da3
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Node.scala
@@ -0,0 +1,12 @@
+package com.astraldb.spec;
+
+case class Node(val name:String, val fields:Seq[Field])
+{
+  def renderName = name+"Node"
+  def enumName = "JITD_NODE_"+name
+  def scope = fields.map { f => f.name -> f.t }.toMap
+
+  override def toString =
+    name + "(" + fields.map { _.toString }.mkString(", ") + ")"
+
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/spec/Pattern.scala b/astral/src/com/astraldb/spec/Pattern.scala
new file mode 100644
index 0000000..d9a2d49
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Pattern.scala
@@ -0,0 +1,223 @@
+package com.astraldb.spec
+
+import com.astraldb.ast._
+import com.astraldb.spec.MatchPattern.Scope
+
+/**
+ * A rule for matching patterns
+ */
+sealed trait MatchPattern
+{
+  /**
+   * Apply the match pattern to a specified abstract syntax tree
+   * 
+   * Return the updated scope, or None if the pattern does not match
+   */
+  def apply(node: AST, scope: Scope): Option[Scope]
+}
+object MatchPattern
+{
+  type Scope = Map[String, AST]
+}
+
+/**
+ * Boolean logic over match patterns
+ */
+sealed trait BooleanMatchPattern extends MatchPattern
+
+
+/**
+ * Boolean not.  
+ */
+case class MatchNot(child: MatchPattern) extends BooleanMatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    child(node, scope) match {
+      case None => Some(Map.empty)
+      case Some(_) => None
+    }
+}
+
+/**
+ * Boolean and
+ */
+case class MatchAnd(children: Seq[MatchPattern]) extends BooleanMatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    children.foldLeft(Some(scope):Option[Scope]){ (scope, child) => 
+      scope.flatMap { child(node, _) }
+    }
+}
+
+/**
+ * Boolean or
+ */
+case class MatchOr(children: Seq[MatchPattern]) extends BooleanMatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+  {
+    children.foldLeft(None: Option[Scope]) { (retScope, child) =>
+      if(retScope.isDefined) { retScope }
+      else { child(node, scope) }
+    }
+  }
+}
+
+/**
+ * Match a node type.  
+ * 
+ * Return a match if the current AST element is a node of the labeled type,
+ * and if all child matchers match as well.
+ */
+case class MatchNode(nodeLabel: String, children: Seq[MatchPattern]) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] =
+    node match {
+      case ANode(label, elements) if label == nodeLabel 
+                                  && elements.size == children.size =>
+        children.zip(elements).foldLeft(Some(scope):Option[Scope]) { case (scope, (child, element)) =>
+          scope.flatMap { child(element, _) }
+        }
+      case _ => None
+    }
+}
+
+/**
+ * Match a node, solely based on its type
+ * 
+ * Return a match if the current AST element is a node of the labeled type.
+ * Ignore the children.
+ */
+case class MatchNodeType(nodeLabel: String) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] =
+    node match {
+      case ANode(label, elements) if label == nodeLabel => Some(scope)
+      case _ => None
+    }
+
+}
+
+/**
+ * Match a node exactly.
+ * 
+ * Return a match if the current AST element is identical to the AST provided
+ * in the pattern
+ */
+case class MatchExact(pattern: AST) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    if(node == pattern){ Some(scope) }
+    else { None }
+}
+
+/**
+ * Match a descendant identified by a provided path of indices
+ * 
+ * The provided path specifies descendants by their positions.  The 0th
+ * index is the first child of a Node or a List AST.  The matcher returns
+ * a match if the specified path exists, and if the provided pattern matches
+ * the element at the specified position.
+ */
+case class MatchPath(path: Seq[Int], pattern: MatchPattern) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    path.foldLeft( Some(node):Option[AST] ) { (target, idx) =>
+      target match {
+        case Some(ANode(_, elements)) if elements.size > idx => Some(elements(idx))
+        case Some(AList(elements)) if elements.size > idx => Some(elements(idx))
+        case _ => None
+      }
+    } match {
+      case None => None
+      case Some(target) => pattern(target, scope)
+    }
+}
+
+/**
+ * Match some descendent.
+ * 
+ * The pattern is applied to all descendents of the current node.  The matcher
+ * returns the first match it finds.
+ */
+case class MatchRecursive(pattern: MatchPattern) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] =
+    node.find { pattern(_, scope) }
+}
+
+/**
+ * Bind the current node to the scope
+ * 
+ * The current node is bound to the scope and the provided pattern is applied
+ * as normal.
+ */
+case class MatchBind(symbol: String, pattern: MatchPattern) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    pattern(node, scope ++ Map(symbol -> node))
+}
+
+/**
+ * Always return a match
+ */
+case object MatchAny extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    Some(scope)
+}
+
+/**
+ * Never return a match
+ */
+case object MatchNone extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] =
+    None
+}
+
+/**
+ * Match the current node against an element of the scope.
+ * 
+ * Returns a match if the provided symbol exists in the scope and the current
+ * node is exactly equal to the symbol's value in the scope.
+ */
+case class MatchLookup(symbol: String) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    scope.get(symbol).flatMap { scopeNode =>
+      if(node == scopeNode){ Some(scope) } else { None }
+    }
+}
+
+/**
+ * Apply a matcher to an element of the scope
+ * 
+ * Returns a match if the provided symbol exists in the scope and the provided
+ * pattern exactly matches the symbol's value in the scope.
+ */
+case class MatchScope(symbol: String, pattern: MatchPattern) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    scope.get(symbol).flatMap { scopeNode =>
+      pattern(scopeNode, scope)
+    }
+}
+
+/**
+ * Apply a matcher to every element of a list
+ * 
+ * Returns a match if the current element is a list and every element of the
+ * list matches the provided pattern
+ */
+case class MatchList(pattern: MatchPattern) extends MatchPattern
+{
+  def apply(node: AST, scope: Scope): Option[Scope] = 
+    node match {
+      case AList(elements) => 
+        elements.foldLeft( Some(scope): Option[Scope] ){ (scope, element) =>
+          scope.flatMap { pattern(element, _) }
+        }
+      case _ => None
+    }
+}
diff --git a/astral/src/com/astraldb/spec/Statement.scala b/astral/src/com/astraldb/spec/Statement.scala
new file mode 100755
index 0000000..0403a40
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Statement.scala
@@ -0,0 +1,128 @@
+package com.astraldb.spec
+
+import scala.language.implicitConversions
+
+object StatementConversions {
+  implicit def seq2block(s:Seq[Statement]): Block = Block(s)
+}
+
+sealed abstract class Statement
+{
+  def disasssembleStatement: Seq[Statement]
+  def reassembleStatement(in: Seq[Statement]): Statement 
+  def rebuildStatement(fn: Statement => Statement): Statement =
+    reassembleStatement(disasssembleStatement.map { fn(_) })
+  def disasssembleExpression: Seq[Expression]
+  def reassembleExpression(in: Seq[Expression]): Statement
+  def rebuildExpression(fn: Expression => Expression): Statement = 
+    reassembleExpression(disasssembleExpression.map { fn(_) })
+      .rebuildStatement { _.rebuildExpression(fn) }
+  
+  def toString(prefix: String): String
+  override def toString: String = toString("")
+
+  def blockSeq: Seq[Statement] = Seq(this)
+  def ++(other: Statement): Block = Block(this.blockSeq ++ other.blockSeq)
+}
+
+case class IfThenElse(condition:Expression, ifTrue:Statement, ifFalse:Statement = Block(Seq())) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq(ifTrue, ifFalse)
+  def reassembleStatement(in: Seq[Statement]): Statement = IfThenElse(condition, in(0), in(1))
+  def disasssembleExpression: Seq[Expression] = Seq(condition)
+  def reassembleExpression(in: Seq[Expression]): Statement = IfThenElse(in(0), ifTrue, ifFalse)
+  def toString(prefix: String) = s"${prefix}if($condition)\n"+ifTrue.toString(prefix+"  ")+s"\n${prefix}else\n"+ifFalse.toString(prefix+"  ")
+}
+case class Declare(name:String, t:Option[Type], v:Expression) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq(v)
+  def reassembleExpression(in: Seq[Expression]): Statement = Declare(name, t, in(0))
+  def toString(prefix: String) = s"${prefix}var $name${t.map { x => ":"+Type.toString(x)}.getOrElse("")} = $v"
+}
+
+case class Assign(name:String, v:Expression, atomic:Boolean = false) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq(v)
+  def reassembleExpression(in: Seq[Expression]): Statement = Assign(name, in(0), atomic)
+  def toString(prefix: String) = s"${prefix}$name = $v"
+}
+
+case class ExtractNode(name:String, v:Expression, nodeHandlers: Seq[(String, Statement)], onFail: Statement) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq(onFail) ++ nodeHandlers.map { _._2 }
+  def reassembleStatement(in: Seq[Statement]): Statement = ExtractNode(name, v, nodeHandlers.zip(in.tail).map { case ((name, _), handler) => (name, handler) }, in(0))
+  def disasssembleExpression: Seq[Expression] = Seq(v)
+  def reassembleExpression(in: Seq[Expression]): Statement = ExtractNode(name, in(0), nodeHandlers, onFail)
+  def toString(prefix: String) = s"${prefix}extract $v into $name { \n"+nodeHandlers.map { 
+                                                              case (nodeType, onMatch) => s"${prefix}  case $nodeType -> \n${onMatch.toString(prefix+"    ")}\n"
+                                                            }.mkString+s"\n${prefix}  else -> \n${onFail.toString(prefix+"     ")}\n${prefix}}"
+}
+case class Block(statements:Seq[Statement]) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = statements
+  def reassembleStatement(in: Seq[Statement]): Statement = Block(in)
+  def disasssembleExpression: Seq[Expression] = Seq()
+  def reassembleExpression(in: Seq[Expression]): Statement = this
+  def toString(prefix: String) = (Seq(prefix+"{")++statements.map{ _.toString(prefix+"  ") }++Seq(prefix+"}")).mkString("\n")
+  override def blockSeq = statements
+}
+case class ForEach(loopvar:String, over:Expression, body:Statement) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq(body)
+  def reassembleStatement(in: Seq[Statement]): Statement = ForEach(loopvar, over, in(0))
+  def disasssembleExpression: Seq[Expression] = Seq(over)
+  def reassembleExpression(in: Seq[Expression]): Statement = ForEach(loopvar, in(0), body)
+  def toString(prefix: String) = s"${prefix}for($loopvar in $over)\n${body.toString(prefix+"  ")}"
+}
+case class Void(v:Expression) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq(v)
+  def reassembleExpression(in: Seq[Expression]): Statement = Void(in(0))
+  def toString(prefix: String) = s"${prefix}void $v"
+}
+case class Return(v:Expression) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq(v)
+  def reassembleExpression(in: Seq[Expression]): Statement = Return(in(0))
+  def toString(prefix: String) = s"${prefix}return $v"
+}
+case class Error(msg:String) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq()
+  def reassembleExpression(in: Seq[Expression]): Statement = this
+  def toString(prefix: String) = prefix+"error: "+msg
+}
+case class Comment(msg:String) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq()
+  def reassembleExpression(in: Seq[Expression]): Statement = this
+  def toString(prefix: String) = prefix+"rem: "+msg
+}
+case class SetRemoveFunction(name:String,nodeType:String,v:Expression) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq()
+  def reassembleExpression(in: Seq[Expression]): Statement = this
+  def toString(prefix: String) = prefix+"removing from set: "+name
+}
+case class SetAddFunction(name:String,nodeType:String,v:Expression) extends Statement
+{
+  def disasssembleStatement: Seq[Statement] = Seq()
+  def reassembleStatement(in: Seq[Statement]): Statement = this
+  def disasssembleExpression: Seq[Expression] = Seq()
+  def reassembleExpression(in: Seq[Expression]): Statement = this
+  def toString(prefix: String) = s"${prefix} adding to set: $v"
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/spec/Type.scala b/astral/src/com/astraldb/spec/Type.scala
new file mode 100755
index 0000000..ca04fb5
--- /dev/null
+++ b/astral/src/com/astraldb/spec/Type.scala
@@ -0,0 +1,37 @@
+package com.astraldb.spec
+
+sealed abstract class Type {
+  def array = TArray(this)
+}
+
+sealed abstract class PrimType extends Type
+
+case class TKey() extends PrimType { override def toString = "key" }
+case class TRecord() extends Type
+
+case class TInt() extends PrimType
+case class TFloat() extends PrimType
+case class TBool() extends PrimType
+case class TArray(t:Type) extends Type
+case class TStruct(fields:Seq[Field]) extends Type
+case class TNodeRef() extends Type
+case class TNode(t:String) extends Type
+case class TIterator() extends Type
+case class THandleRef() extends Type
+object Type
+{
+  def toString(t: Type): String =
+    t match {
+      case TKey() => "key"
+      case TRecord() => "record"
+      case TInt() => "int"
+      case TFloat() => "float"
+      case TBool() => "bool"
+      case TArray(nested) => s"array[${Type.toString(nested)}]"
+      case TStruct(fields) => s"struct[${fields.map { _.toString }.mkString{", "}}]"
+      case TNodeRef() => "noderef"
+      case THandleRef() => "handleref"
+      case TNode(t) => s"node[$t]"
+      case TIterator() => "iterator"
+    }
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/typecheck/FunctionSignature.scala b/astral/src/com/astraldb/typecheck/FunctionSignature.scala
new file mode 100755
index 0000000..e6960c7
--- /dev/null
+++ b/astral/src/com/astraldb/typecheck/FunctionSignature.scala
@@ -0,0 +1,33 @@
+package com.astraldb.typecheck
+
+import com.astraldb.spec._
+
+abstract class FunctionSignature()
+{
+  def apply(args:Seq[Type]): Option[Type]
+  def name: String
+}
+
+class FunctionArgError(function:FunctionSignature, args:Seq[Type]) extends Exception
+{
+  override def toString =
+    function.toString + " <- (" + args.map { Type.toString(_) }.mkString(", ") + ")"
+}
+
+class SimpleFunctionSignature(val name:String, args:Seq[Type], ret:Option[Type]) extends FunctionSignature
+{
+  def apply(cmpArgs:Seq[Type]) = 
+    if(args == cmpArgs){ ret; }
+    else { throw new FunctionArgError(this, cmpArgs) } 
+  override def toString: String = 
+    ret.getOrElse("void").toString+" "+name+"("+args.map { Type.toString(_) }.mkString(", ")+")"
+}
+
+object FunctionSignature 
+{
+  def apply(name:String, args:Seq[Type], ret:Type) = 
+    new SimpleFunctionSignature(name, args, Some(ret))
+  def apply(name:String, args:Seq[Type]) = 
+    new SimpleFunctionSignature(name, args, None)
+
+}
\ No newline at end of file
diff --git a/astral/src/com/astraldb/typecheck/Typechecker.scala b/astral/src/com/astraldb/typecheck/Typechecker.scala
new file mode 100755
index 0000000..57bae59
--- /dev/null
+++ b/astral/src/com/astraldb/typecheck/Typechecker.scala
@@ -0,0 +1,295 @@
+package com.astraldb.typecheck
+
+import com.astraldb.spec._
+
+class TypeError(msg: String, ctx: Expression, scope:Map[String, Type]) extends Exception(msg+" in "+ctx.toString)
+{
+  override def toString:String = {
+    val scopeLen = scope.map { case (k, _ ) => k.length }.max
+    "-----------------------\n"+msg + " in " + ctx + "\n\n"+"---- Current Scope ----\n"+
+      scope.map { case (k, t) => "   " + k.padTo(scopeLen, " ").mkString + "  <- " + t }.mkString("\n")+
+      "\n-----------------------"
+  }
+
+  def rebind(newCtx:Expression) = new TypeError(msg, newCtx, scope)
+  def rebind(newCtx:Statement) = new StatementError(msg, Seq(newCtx), scope)
+}
+
+class StatementError(msg: String, ctx: Seq[Statement], scope:Map[String, Type]) extends Exception(msg+" in "+ctx(0).toString)
+{
+  override def toString:String = {
+    val scopeLen = scope.map { case (k, _ ) => k.length }.max
+    "-----------------------\n"+msg + " in " + ctx.head + "\n\n"+"---- Current Scope ----\n"+
+      scope.map { case (k, t) => "   " + k.padTo(scopeLen, " ").mkString + "  <- " + t }.mkString("\n")+
+      "\n-----------------------"+
+      (if(ctx.length > 1) { "\n -- in -- \n"+ctx.tail.map { _.toString }.mkString("\n -- in -- \n")} else { "" })
+  }
+  def trace(stmt: Statement) = new StatementError(msg, ctx :+ stmt, scope)
+}
+
+
+class Typechecker(functions: Map[String, FunctionSignature], nodeTypes: Map[String, Node]) {
+
+  def comparisonCompatible(t1:Type, t2:Type): Boolean =
+  {
+
+    if(t1 == t2) { return true; }
+    (t1, t2) match {
+      case (TIterator(), _)    => return comparisonCompatible(TRecord(), t2)
+      case (_, TIterator())    => return comparisonCompatible(t1, TRecord())
+      case (TKey(), TRecord()) => return true
+      case (TRecord(), TKey()) => return true
+      case _ => return false
+    }
+  }
+  
+  def typeOf(e: Expression, scope: Map[String, Type]): Type = 
+  {
+    val error = (msg:String) => throw new TypeError(msg, e, scope)
+    val recur = (r:Expression) => try { typeOf(r, scope) } catch { case t: TypeError => throw t.rebind(e) }
+    e match {
+      case c:Constant => c.t
+      case ArraySubscript(arr, _) => {
+        recur(arr) match { 
+          case TArray(nested) => nested
+          case _ => error("Subscript of Non-Array: "+arr)
+        }
+      }
+      case StructSubscript(struct, subscript) => {
+        recur(struct) match {
+          case TStruct(fields) => 
+            fields.find { _.name.equals(subscript) } match {
+              case Some(field) => field.t
+              case None => error("Invalid Struct Subscript: "+subscript)
+            }
+          case _ => error("Subscript of Non-Struct: "+struct)
+        }
+      }
+      case NodeSubscript(node, subscript) => {
+        recur(node) match {
+          case TNode(nodeType) => 
+            nodeTypes(nodeType).fields.find { _.name.equals(subscript) } match {
+              case Some(field) => field.t
+              case None => error("Invalid Node Subscript: "+subscript)
+            }
+          case _ => error("Subscript of Non-Node: "+node)
+        }
+      }
+      case Cmp(op, a, b) => {
+        if(comparisonCompatible(recur(a), recur(b))){
+          return TBool()
+        } else {
+          error("Invalid Comparison")
+        }
+      }
+      case Arith(_, a, b) => {
+        (recur(a), recur(b)) match {
+          case (TInt(), TInt()) => return TInt()
+          case (TInt(), TFloat())
+             | (TFloat(), TInt())
+             | (TFloat(), TFloat()) => return TFloat()
+          case _ => error("Invalid Arithmetic")
+        }
+      }
+      case FunctionCall(name, args) => {
+        try {
+          functions.getOrElse(name, {
+            error("Undefined function")
+          })(args.map { recur }).getOrElse { error("Using return value from void function") }
+        } catch { 
+          case e:FunctionArgError => error(e.toString)
+        }
+      }
+      case FunctionalIfThenElse(c, t, e) => {
+        (recur(c), recur(t), recur(e)) match {
+          case (TBool(), a, b) if a == b => a
+          case (TBool(), _, _) => error("Incompatible functional then-else clauses")
+          case (_, _, _) => error("Non-Boolean if-then-else condition")
+        }
+      }
+      case Var(name) => {
+        scope.get(name) match {
+          case Some(t) => t
+          case None => error(s"Variable '$name' not in scope")
+        }
+      }
+      case WrapNode(target) => {
+        recur(target) match {
+          case TNode(_) => TNodeRef()  
+          case _ => error("Can't wrap a non-node")
+        }
+      }
+      case UnWrapHandle(target) => {
+        recur(target) match {
+          case THandleRef() => TNodeRef() 
+          //case TNodeRef() => TNodeRef() 
+          case _ => error("Can't unwrap a non-handle")
+        }
+      }
+      case WrapNodeRef(target) => {
+        recur(target) match {
+          case TNodeRef() => THandleRef()  
+          case _ => error("Can't wrap a non-node-ref")
+        }
+      }
+      case MakeNode(nodeType, fields) => {
+        for( (field, expr) <- nodeTypes(nodeType).fields.zip(fields)){
+          if(recur(expr) != field.t) { 
+            error("Invalid node constructor")
+          }
+        }
+        TNode(nodeType)
+      }
+    case NodeCast(nodeType,node, subscript) => {
+      recur(node) match {
+          case TNode(nodeType) => 
+            nodeTypes(nodeType).fields.find { _.name.equals(subscript) } match {
+              case Some(field) => field.t
+              case None => error("Invalid Node Subscript: "+subscript)
+            }
+          case _ => error("Subscript of Non-Node: "+node)
+        }
+
+    }
+    }
+  }
+
+  def check(stmt: Statement, scope: Map[String, Type], returnType:Option[Type]): Map[String, Type] =
+  {
+    val exprType = (e:Expression) => try { typeOf(e, scope) } catch { case e:TypeError => throw e.rebind(stmt) }
+    val error = (msg:String) => throw new StatementError(msg, Seq(stmt), scope)
+    val recur = (rstmt: Statement, rscope: Map[String, Type]) => try { check(rstmt, rscope, returnType) } catch { case e:StatementError => throw e.trace(stmt) }
+    stmt match { 
+      case Block(elems) => {
+        elems.foldLeft(scope) { (currScope, currStmt) => 
+          recur(currStmt, currScope)
+        }
+        scope
+      }
+      case Assign(tgt, expr, false) => {
+        val tgtType = scope.getOrElse(tgt, { error("Assignment to undefined variable: "+tgt) })
+
+        if(exprType(expr) != tgtType){
+         error("Assignment to "+tgt+" of incorrect type")
+        }
+        if(tgtType == TNodeRef())
+        {
+          error("Non-atomic assignment to a NodeRef")
+        }
+        if(tgtType == THandleRef()){
+         error("Non-atomic assignment to a NodeHandle")
+        }
+        scope
+      }
+      
+      case Assign(tgt,expr,true) => {
+        val tgtType = scope.getOrElse(tgt, { error("Assignment to undefined variable: "+tgt) })
+        if(tgtType != THandleRef() || exprType(expr)!= TNodeRef())
+        {
+          error("Atomic assignment into wrong types ")
+        }
+        scope
+      }
+
+      case Declare(tgt, tOption, expr) => {
+        if(scope contains tgt) {
+          error("Overriding existing variable")
+        }
+        val tRet = tOption match {
+          case Some(t) => if(t != exprType(expr)){ 
+            error("Declaring expression of incorrect type") 
+          } else { t } 
+          case None => exprType(expr)
+        }
+        scope + (tgt -> tRet)
+      }
+      
+      case ExtractNode(name, expr, matchers, onFail) => {
+        if(scope contains name) { 
+          error("Overriding existing variable")
+        }
+        val exp = exprType(expr)
+        if(exp != THandleRef()) {
+          error("Doesn't evaluate to an (extractable) node/Handle reference")
+        }
+        for( (nodeType, handler) <- matchers ){
+          if(!(nodeTypes contains nodeType)) {
+            error(s"Invalid Node Type: '$nodeType'")
+          }
+          recur(handler, scope + (name -> TNode(nodeType)))
+        }
+        recur(onFail, scope)
+        scope
+      }
+      
+      case Return(expr) => {
+        if(exprType(expr) != returnType.getOrElse { 
+          error(s"Invalid Return Type (Found: ${exprType(expr)}; Void Function)")
+        }) { 
+          error(s"Invalid Return Type (Found: ${exprType(expr)}; Expected: $returnType)")
+        }
+        scope
+      }
+      case Void(expr @ FunctionCall(name, args)) => {
+        try {
+          functions.getOrElse(name, {
+            error("Undefined function")
+          })(args.map { exprType(_) })
+        } catch { 
+          case e:FunctionArgError => error(e.toString)
+        }
+        scope
+      }
+      case Void(expr) => {
+        exprType(expr)
+        scope
+      }
+      case ForEach(loopvar, expr, body) => {
+        if(scope contains loopvar) {
+          error("Overriding existing variable")
+        }
+        exprType(expr) match {
+          case TArray(nested) => 
+            recur(body, scope + (loopvar -> nested))
+          case _ => 
+            error("Invalid loop target")
+        }
+        scope
+      }
+      case IfThenElse(c, t, e) => {
+        if(exprType(c) != TBool()){
+          error("Invalid if-then-else condition")
+        }
+        recur(t, scope)
+        recur(e, scope)
+        scope
+      }
+      case Error(_) => scope
+      case Comment(_) => scope
+      case SetRemoveFunction(_,_,_) => scope 
+      case SetAddFunction(_,_,_) => scope 
+      
+    }
+  }
+
+  def check(globals: Map[String,Type])(fn: FunctionDefinition): FunctionDefinition =
+  {
+    check(fn.body, globals ++ fn.args.map { case (name, t, _) => name -> t }.toMap, fn.ret)
+    return fn
+  }
+  def check(globals: (String,Type)*)(fn: FunctionDefinition): FunctionDefinition =
+    check(globals.toMap)(fn)
+
+  def check(fn: FunctionDefinition): FunctionDefinition =
+  {
+    check(fn.body, fn.args.map { case (name, t, _) => name -> t }.toMap, fn.ret)
+    return fn
+  }
+
+  def withFunctions(newFuncs: Map[String, FunctionSignature]): Typechecker =
+    new Typechecker(functions ++ newFuncs, nodeTypes)
+
+  def withFunctions(newFuncs: (String, FunctionSignature)*): Typechecker =
+    withFunctions(newFuncs.toMap)
+
+}
\ No newline at end of file
diff --git a/build.sc b/build.sc
new file mode 100644
index 0000000..2b7095c
--- /dev/null
+++ b/build.sc
@@ -0,0 +1,30 @@
+import mill._
+import mill.scalalib._
+import mill.scalalib.publish._
+
+object astral extends ScalaModule with PublishModule {
+  val VERSION       = "0.0.1-SNAPSHOT"
+
+  def scalaVersion = "3.2.1"
+
+  def mainClass = Some("com.astraldb.Astral")
+
+  /*************************************************
+   *** Backend Dependencies
+   *************************************************/
+  // def ivyDeps = Agg(
+  // )
+
+  def publishVersion = VERSION
+  override def pomSettings = PomSettings(
+    description = "The Astral Compiler",
+    organization = "com.astraldb",
+    url = "http://astraldb.com",
+    licenses = Seq(License.`Apache-2.0`),
+    versionControl = VersionControl.github("UBOdin", "astral"),
+    developers = Seq(
+      Developer("okennedy", "Oliver Kennedy", "https://odin.cse.buffalo.edu"),
+    )
+  )
+}
+