1 files changed, 85 insertions, 0 deletions
diff --git a/ast.h b/ast.h
new file mode 100644
index 0000000..c0b0d90
--- /dev/null
+++ b/ast.h
@@ -0,0 +1,85 @@
+#pragma once
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <cstdlib>
+#include "global.h"
+#include "indirect.h"
+
+using namespace std;
+
+
+class AST;
+
+
+using Number = i64;
+using String = string;
+using Name = string;
+using Index = i64;
+class Terms : public vector<AST>{
+public:
+	using vector<AST>::vector;
+	using vector<AST>::operator=;
+};
+class Lambda{
+public:
+	Name arg; // if empty, then can only be referred to with indices
+	Indirect<AST> body=Indirect<AST>::makeEmpty();
+
+	Lambda();
+	Lambda(const Name &arg,const AST &ast);
+};
+using Native = function<AST(const AST&)>;
+
+
+
+class ParseError : public runtime_error{
+public:
+	explicit ParseError(const string &what_arg);
+	explicit ParseError(const char *what_arg);
+};
+
+class AST{
+public:
+	enum class Type{
+		number,
+		string,
+		name,
+		index,
+		tuple,
+		lambda,
+		native,
+	};
+
+	Type type;
+	Number numval;
+	String strval;
+	Name nameval;
+	Index indexval;
+	Terms terms;
+	Lambda lambdaval;
+	Native nativeval;
+
+	bool quoted=false;
+
+private:
+	class Tokeniser;
+	AST& parse(Tokeniser &tokeniser);
+
+public:
+	AST(); // initialises to nil value ()
+	explicit AST(const string &source); // parses source
+	explicit AST(const char *source); // parses source
+
+	static AST makeNumber(Number numval);
+	static AST makeString(String strval);
+	static AST makeName(Name nameval);
+	static AST makeIndex(Index indexval);
+	static AST makeTuple(Terms terms);
+	static AST makeLambda(Lambda lambdaval);
+	static AST makeLambda(const Name &arg,const AST &body);
+	static AST makeNative(const Native &native);
+};
+
+ostream& operator<<(ostream &os,const AST &ast);