1 files changed, 160 insertions, 0 deletions
diff --git a/expressions.h b/expressions.h
new file mode 100644
index 0000000..2ff9c1a
--- /dev/null
+++ b/expressions.h
@@ -0,0 +1,160 @@
+#ifndef __EXPRESSIONS_H
+#define __EXPRESSIONS_H
+
+#include <glib.h>
+
+#include "undo.h"
+
+template <typename Type>
+class ValueStack {
+	int size;
+
+	Type *stack;
+	Type *top;
+
+public:
+	ValueStack(int _size = 1024) : size(_size)
+	{
+		top = stack = new Type[size];
+	}
+
+	~ValueStack()
+	{
+		delete stack;
+	}
+
+	inline int
+	items(void)
+	{
+		return (top - stack)/sizeof(Type);
+	}
+
+	inline Type &
+	push(Type value, int index = 1)
+	{
+		for (int i = -index + 1; i; i++)
+			top[i+1] = top[i];
+
+		top++;
+		return peek(index) = value;
+	}
+
+	inline Type
+	pop(int index = 1)
+	{
+		Type v = peek(index);
+
+		top--;
+		while (--index)
+			top[-index] = top[-index + 1];
+
+		return v;
+	}
+
+	inline Type &
+	peek(int index = 1)
+	{
+		return top[-index];
+	}
+};
+
+template <typename Type>
+class UndoTokenPush : public UndoToken {
+	ValueStack<Type> *stack;
+
+	Type	value;
+	int	index;
+
+public:
+	UndoTokenPush(ValueStack<Type> &_stack, Type _value, int _index = 1)
+		     : stack(&_stack), value(_value), index(_index) {}
+
+	void
+	run(void)
+	{
+		stack->push(value, index);
+	}
+};
+
+template <typename Type>
+class UndoTokenPop : public UndoToken {
+	ValueStack<Type> *stack;
+
+	int index;
+
+public:
+	UndoTokenPop(ValueStack<Type> &_stack, int _index = 1)
+		    : stack(&_stack), index(_index) {}
+
+	void
+	run(void)
+	{
+		stack->pop(index);
+	}
+};
+
+/*
+ * Arithmetic expression stacks
+ */
+extern class Expressions {
+	/* reflects also operator precedence */
+	enum Operator {
+		OP_NIL = 0,
+		OP_POW,		// ^*
+		OP_MUL,		// *
+		OP_DIV,		// /
+		OP_MOD,		// ^/
+		OP_ADD,		// +
+		OP_SUB,		// -
+		OP_AND,		// &
+		OP_OR,		// #
+				// pseudo operators:
+		OP_BRACE,
+		OP_LOOP,
+		OP_NUMBER
+	};
+
+	ValueStack<gint64>	numbers;
+	ValueStack<Operator>	operators;
+
+	gint			num_sign;
+	gint			radix;
+
+public:
+	Expressions() : num_sign(1), radix(10) {}
+
+	void set_num_sign(gint sign);
+	void set_radix(gint r);
+
+	gint64 push(gint64 number);
+
+	gint64 pop_num(int index = 1);
+	gint64 pop_num_calc(int index, gint64 imply);
+	inline gint64
+	pop_num_calc(int index = 1)
+	{
+		return pop_num_calc(index, num_sign);
+	}
+
+	gint64 add_digit(gchar digit);
+
+	Operator push(Operator op);
+	Operator push_calc(Operator op);
+
+	Operator pop_op(int index = 1);
+
+	void calc(void);
+
+	void eval(bool pop_brace = false);
+
+	int args(void);
+	inline int
+	first_op(void)
+	{
+		return args() + 1;
+	}
+
+	void discard_args(void);
+} expressions;
+
+#endif