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Support * and / in reader

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This commit is contained in:
Camden Dixie O'Brien 2024-10-24 20:24:22 +01:00
parent 06bf0a1930
commit 9988f6dcb8
2 changed files with 100 additions and 10 deletions
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56
lib/reader.c
View File

@ -24,7 +24,7 @@ static int parse_number(
return used;
}
static int parse_expression(
static int parse_term(
memory_pool_t *pool, const char *input, int len, expression_t **out)
{
int result, used = 0;
@ -39,16 +39,12 @@ static int parse_expression(
const expression_t *term0 = expr;
operator_t operator;
switch (input[used]) {
case '+':
operator= OPERATOR_ADD;
if ('*' == input[used])
operator = OPERATOR_MULTIPLY;
else if ('/' == input[used])
operator = OPERATOR_DIVIDE;
else
break;
case '-':
operator= OPERATOR_SUBTRACT;
break;
default:
return 0;
}
++used;
expression_t *term1;
@ -68,6 +64,46 @@ static int parse_expression(
return used;
}
static int parse_expression(
memory_pool_t *pool, const char *input, int len, expression_t **out)
{
int result, used = 0;
expression_t *expr;
result = parse_term(pool, input, len, &expr);
if (0 >= result)
return 0;
used += result;
while (len > used) {
const expression_t *term0 = expr;
operator_t operator;
if ('+' == input[used])
operator = OPERATOR_ADD;
else if ('-' == input[used])
operator = OPERATOR_SUBTRACT;
else
break;
++used;
expression_t *term1;
result = parse_term(pool, input + used, len - used, &term1);
if (0 >= result)
return 0;
used += result;
expr = allocate_expression(pool);
expr->is_number = false;
expr->application.operator= operator;
expr->application.operands[0] = term0;
expr->application.operands[1] = term1;
}
*out = expr;
return used;
}
const expression_t *
read_expression(memory_pool_t *pool, const char *input, int len)
{

54
tests/reader_tests.c
View File

@ -89,6 +89,58 @@ input_1_plus_2_plus_3_is_parsed_as_a_left_nested_application(void)
ASSERT_EQUAL(3, operand1->number);
}
static void
input_1_times_2_times_3_is_parsed_as_a_left_nested_application(void)
{
init_memory_pool(&pool);
const expression_t *result = read_expression(&pool, "1*2*3", 5);
ASSERT_NOT_NULL(result);
ASSERT_FALSE(result->is_number);
ASSERT_EQUAL(OPERATOR_MULTIPLY, result->application.operator);
const expression_t *operand0 = result->application.operands[0];
ASSERT_NOT_NULL(operand0);
ASSERT_FALSE(operand0->is_number);
ASSERT_EQUAL(OPERATOR_MULTIPLY, operand0->application.operator);
ASSERT_NOT_NULL(operand0->application.operands[0]);
ASSERT_TRUE(operand0->application.operands[0]->is_number);
ASSERT_EQUAL(1, operand0->application.operands[0]->number);
ASSERT_NOT_NULL(operand0->application.operands[1]);
ASSERT_TRUE(operand0->application.operands[1]->is_number);
ASSERT_EQUAL(2, operand0->application.operands[1]->number);
const expression_t *operand1 = result->application.operands[1];
ASSERT_NOT_NULL(operand1);
ASSERT_TRUE(operand1->is_number);
ASSERT_EQUAL(3, operand1->number);
}
static void
input_1_plus_2_times_3_is_parsed_as_a_right_nested_application(void)
{
init_memory_pool(&pool);
const expression_t *result = read_expression(&pool, "1+2*3", 5);
ASSERT_NOT_NULL(result);
ASSERT_FALSE(result->is_number);
ASSERT_EQUAL(OPERATOR_ADD, result->application.operator);
const expression_t *operand0 = result->application.operands[0];
ASSERT_NOT_NULL(operand0);
ASSERT_TRUE(operand0->is_number);
ASSERT_EQUAL(1, operand0->number);
const expression_t *operand1 = result->application.operands[1];
ASSERT_NOT_NULL(operand1);
ASSERT_FALSE(operand1->is_number);
ASSERT_EQUAL(OPERATOR_MULTIPLY, operand1->application.operator);
ASSERT_NOT_NULL(operand1->application.operands[0]);
ASSERT_TRUE(operand1->application.operands[0]->is_number);
ASSERT_EQUAL(2, operand1->application.operands[0]->number);
ASSERT_NOT_NULL(operand1->application.operands[1]);
ASSERT_TRUE(operand1->application.operands[1]->is_number);
ASSERT_EQUAL(3, operand1->application.operands[1]->number);
}
int main(void)
{
TESTING_BEGIN();
@ -100,5 +152,7 @@ int main(void)
RUN_TEST(
input_6_minus_2_with_no_spaces_is_read_as_a_subtract_application);
RUN_TEST(input_1_plus_2_plus_3_is_parsed_as_a_left_nested_application);
RUN_TEST(input_1_times_2_times_3_is_parsed_as_a_left_nested_application);
RUN_TEST(input_1_plus_2_times_3_is_parsed_as_a_right_nested_application);
TESTING_END();
}