(Somewhat adapted) code and solutions from the book "Build Your Own Lisp"
http://www.buildyourownlisp.com
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84 lines
2.2 KiB
84 lines
2.2 KiB
#include <stdio.h>
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#include <stdlib.h>
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#include "../mpc/mpc.h"
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/* If we are on Windows compile these functions */
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#ifdef _WIN32
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#include <string.h>
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#include <assert.h>
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static char buffer[2048];
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/* Fake readline function */
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char* readline(char* prompt) {
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fputs(prompt, stdout);
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fgets(buffer, 2048, stdin);
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char* cpy = malloc(strlen(buffer)+1);
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assert(cpy != NULL)
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strcpy(cpy, buffer);
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cpy[strlen(cpy)-1] = '\0';
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return cpy;
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}
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/* Fake add_history function */
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void add_history(char* unused) {}
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/* Otherwise include the editline headers
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could use __APPLE__ for detection of OSX */
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#else
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#include <editline/readline.h>
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#endif
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int main(int argc, char const *argv[])
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{
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/* Create some parsers */
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mpc_parser_t* Number = mpc_new("number");
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mpc_parser_t* Operator = mpc_new("operator");
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mpc_parser_t* Expr = mpc_new("expr");
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mpc_parser_t* Lispy = mpc_new("lispy");
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/* Define them with the following language */
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mpca_lang(MPCA_LANG_DEFAULT,
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" \
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number : /-?[0-9]+/ ; \
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operator : '+' | '-' | '*' | '/' ; \
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expr : <number> | '(' <operator> <expr>+ ')' ; \
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lispy : /^/ <operator> <expr>+ /$/ ; \
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",
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Number, Operator, Expr, Lispy);
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/* Print version and exit information */
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puts("Lispy version 0.0.0.0.1");
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puts("Press Ctrl+c to exit\n");
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/* In a never ending loop */
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while (1) {
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/* Output our prompt and get input */
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char* input = readline("lispy> ");
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/* Add input to history */
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add_history(input);
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/* Attempt to parse the user input */
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mpc_result_t r;
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if (mpc_parse("<stdin>", input, Lispy, &r)) {
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/* On success print the AST */
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mpc_ast_print(r.output);
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mpc_ast_delete(r.output);
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} else {
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/* Otherwise print the error */
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mpc_err_print(r.error);
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mpc_err_delete(r.error);
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}
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/* Free retrieved input */
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free(input);
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}
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/* Undefine and delete our parsers */
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mpc_cleanup(4, Number, Operator, Expr, Lispy);
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return 0;
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}
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