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evalexpr: parse: parse multi-char prefix operators

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This commit is contained in:
Bruno BELANYI 2020-10-31 16:59:06 +01:00
parent 10c7a96deb
commit b12c3562ec
1 changed files with 32 additions and 26 deletions
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58
src/parse/climbing_parse.c
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@ -4,21 +4,25 @@
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include "ast/ast.h"
#define UNREACHABLE() __builtin_unreachable()
#define ARR_SIZE(Arr) (sizeof(Arr) / sizeof(*Arr))
#define OP_STRING(...) (const char[]){__VA_ARGS__}
#define OP_SIZE(...) (sizeof(OP_STRING(__VA_ARGS__)) - 1)
static const struct {
const char *op;
const size_t op_len;
const enum op_kind kind;
const int prio;
const enum { ASSOC_LEFT, ASSOC_RIGHT, ASSOC_NONE } assoc;
const enum { OP_INFIX, OP_PREFIX, OP_POSTFIX } fix;
} ops[] = {
# define OP(Kind, Prio, Assoc, Fix, /* Operator string */ ...) \
[Kind] = { (const char[]){__VA_ARGS__}, Kind, Prio, Assoc, Fix, },
{ OP_STRING(__VA_ARGS__), OP_SIZE(__VA_ARGS__), Kind, Prio, Assoc, Fix, },
#include "operators.inc"
};
@ -45,13 +49,26 @@ static enum op_kind char_to_binop(char c)
UNREACHABLE();
}
static enum op_kind char_to_prefix(char c)
static size_t parse_prefix(enum op_kind *op, const char **input)
{
for (size_t i = 0; i < ARR_SIZE(ops); ++i)
if (ops[i].fix == OP_PREFIX && c == ops[i].op[0])
return ops[i].kind;
skip_whitespace(input);
UNREACHABLE();
size_t best_len = 0;
for (size_t i = 0; i < ARR_SIZE(ops); ++i)
{
if (ops[i].fix != OP_PREFIX) // Only look at prefix operators
continue;
if (ops[i].op_len <= best_len) // Only look at longer operators
continue;
if (strncmp(*input, ops[i].op, ops[i].op_len) == 0)
{
best_len = ops[i].op_len;
*op = ops[i].kind;
}
}
// Return how many characters should be skipped
return best_len;
}
static enum op_kind char_to_postfix(char c)
@ -72,15 +89,6 @@ static bool is_binop(char c)
return false;
}
static bool is_prefix(char c)
{
for (size_t i = 0; i < ARR_SIZE(ops); ++i)
if (ops[i].fix == OP_PREFIX && c == ops[i].op[0])
return true;
return false;
}
static bool is_postfix(char c)
{
for (size_t i = 0; i < ARR_SIZE(ops); ++i)
@ -159,14 +167,14 @@ static bool update_op(enum op_kind *op, const char **input)
skip_whitespace(input);
char c = *input[0];
if (is_binop(c))
if (is_binop(c)) // FIXME: Use string
{
*op = char_to_binop(c);
*op = char_to_binop(c); // FIXME: Use string
return true;
}
if (is_postfix(c))
if (is_postfix(c)) // FIXME: Use string
{
*op = char_to_postfix(c);
*op = char_to_postfix(c); // FIXME: Use string
return true;
}
@ -186,7 +194,7 @@ static struct ast_node *climbing_parse_internal(const char **input, int prec)
{
const char c = *input[0];
eat_char(input);
if (is_binop(c))
if (is_binop(c)) // FIXME: Use string
{
struct ast_node *rhs =
climbing_parse_internal(input, right_prec(op));
@ -232,16 +240,14 @@ static bool my_atoi(const char **input, int *val)
static struct ast_node *parse_operand(const char **input)
{
skip_whitespace(input); // Whitespace is not significant
struct ast_node *ast = NULL;
int val = 0;
if (is_prefix(*input[0]))
size_t skip = 0;
enum op_kind op;
if ((skip = parse_prefix(&op, input))) // Removes whitespace as side-effect
{
enum op_kind op = char_to_prefix(*input[0]);
// Remove the operator
eat_char(input);
*input += skip; // Skip the parsed operator
ast = climbing_parse_internal(input, next_prec(op));
if (!ast)