suguanYang · May 5, 2019 09:53
diff --git a/gistfile1.txt b/gistfile1.txt
 The idea of *shunting yard algorithm* is to keep operators on a stack until their operands have been parsed. The operands are
 kept on a second stack. The *shunting yard algorithm* can be used to directly evaluate expressions as they are parsed, to create
 a reverse Polish notation of an infix expression, or to create an AST. I'll create an AST, so my operand stacks will contain trees

 The key to the algorithm is to keep the operators on the operator stack odered by precedence(lowest at bottom and highest at the top)
 at least in the absence of parenthese. Before pushing an operator onto the operator stack, all higher precedence operators are cleard
 from the stack. Clearing an operator consists of removing the operator from the operator stack and its operands from the operand stack
 making a new tree, and pushing that tree onto the operand stack. At the end of an expression the remaining operators are put into
 trees with their operands and that is that.
	The idea of shunting yard algorithm is to keep operators on a stack until their operands have been parsed. The operands are
	kept on a second stack. The shunting yard algorithm can be used to directly evaluate expressions as they are parsed, to create
	a reverse Polish notation of an infix expression, or to create an AST. I'll create an AST, so my operand stacks will contain trees

	The key to the algorithm is to keep the operators on the operator stack odered by precedence(lowest at bottom and highest at the top)
	at least in the absence of parenthese. Before pushing an operator onto the operator stack, all higher precedence operators are cleard
	from the stack. Clearing an operator consists of removing the operator from the operator stack and its operands from the operand stack
	making a new tree, and pushing that tree onto the operand stack. At the end of an expression the remaining operators are put into
	trees with their operands and that is that.