c_cpp 一种解析调用pantry解析的新方法，可用于解析非嵌套语言。

Posted 2021-05-14

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

/*Pantry Parsing*/

//implements pantry parsing, a parsing which works for any order of operators, prefix, infix or postfix.

#define ADV_WS(chPtr) while(isspace(*chPtr)) chPtr++

#define IS_NUM_START(chPtr) (isdigit(*chPtr) || *chPtr == '-' && isdigit(chPtr[1]))

//initalizer for parse result struct
#define INIT_OPEVENT(opeve) do { \
	opeve.first = 0; \
	opeve.second = 0; \
	opeve.op = 0; \
} while (0)

//quickly determines if chPtr is at operator
#define PRS_OPERATOR(chPtr, opVar) switch(*chPtr) { \
	case '+': \
	   opVar = Operator_Add; \
	   chPtr++; \
	   break; \
	case '-': \
	   if(chPtr[1] == '>')  { \
	   	opVar = Operator_Arrow; \
	   	chPtr += 2; \
	   } \
	   else { \
	   	 opVar = Operator_Sub; \
	   	 chPtr++; \
	   } \
	   break; \
	case '*': \
	   opVar = Operator_Mul; \
	   chPtr++; \
	   break; \
	default: \
	   opVar = Operator_Null; \
	   chPtr++; \
}

//main overhead parsing macro
// Must use or logical so not done till all 3 are done
#define PRS_EVENT(opeve ,chPtr) while(!opeve.first || !opeve.second || !opeve.op) { \
    ADV_WS(chPtr); \
	if(isdigit(*chPtr)) { \
          if(!opeve.first) opeve.first = strtol(chPtr, &chPtr, 10);\
          else if(!opeve.second) opeve.second = strtol(chPtr, &chPtr, 10);\
	} \
	if(!opeve.op) PRS_OPERATOR(chPtr, opeve.op);\
}





struct Reader
{
	char* begin;
	char* end;
};

typedef struct Reader Reader;

enum Operator
{
	Operator_Null,
	Operator_Add,
	Operator_Sub,
	Operator_Mul,
	Operator_Arrow //more than 1 char
};

typedef enum Operator Operator;

//struct to hold pantry parse results
struct OpEvent
{
	long first;
	long second;
	Operator op;
};

typedef struct OpEvent OpEvent;





int main(int argc, char const *argv[])
{
	OpEvent tester;
	INIT_OPEVENT(tester);
	char* code = " 33333 -> 55  88 -> *";
	PRS_EVENT(tester, code);
	printf(" code is '%s', op is %d, first is %ld, second is %ld\n", code, tester.op, tester.first, tester.second);