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Handle nesting and subtraction in reader

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This commit is contained in:
Camden Dixie O'Brien 2024-10-24 17:35:42 +01:00
parent 79494cd0ba
commit d4855813a2
3 changed files with 76 additions and 7 deletions
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8
lib/include/expression.h
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@ -4,10 +4,10 @@
#include <stdbool.h>
typedef enum {
OPERATOR_ADD,
OPERATOR_SUBTRACT,
OPERATOR_MULTIPLY,
OPERATOR_DIVIDE,
OPERATOR_ADD = 0,
OPERATOR_SUBTRACT = 1,
OPERATOR_MULTIPLY = 2,
OPERATOR_DIVIDE = 3,
} operator_t;
struct _expression_t;

21
lib/reader.c
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@ -3,6 +3,10 @@
#include <ctype.h>
#include <stddef.h>
static int parse_expression(
memory_pool_t *pool, const char *input, int remaining,
expression_t *out);
static int parse_number(
memory_pool_t *pool, const char *input, int remaining, expression_t *out)
{
@ -35,14 +39,25 @@ static int parse_application(
remaining -= result;
input += result;
if (remaining <= 0 || *input != '+')
if (remaining <= 0)
return 0;
operator_t operator;
switch (*input) {
case '+':
operator= OPERATOR_ADD;
break;
case '-':
operator= OPERATOR_SUBTRACT;
break;
default:
return 0;
}
++used;
--remaining;
++input;
expression_t *operand1 = allocate_expression(pool);
result = parse_number(pool, input, remaining, operand1);
result = parse_expression(pool, input, remaining, operand1);
if (0 == result)
return 0;
used += result;
@ -50,7 +65,7 @@ static int parse_application(
input += result;
out->is_number = false;
out->application.operator = OPERATOR_ADD;
out->application.operator= operator;
out->application.operands[0] = operand0;
out->application.operands[1] = operand1;

54
tests/reader_tests.c
View File

@ -39,12 +39,66 @@ static void input_1_plus_2_with_no_spaces_is_read_as_an_add_application(void)
ASSERT_EQUAL(OPERATOR_ADD, result->application.operator);
}
static void operands_of_15_plus_54_are_read_as_numbers(void)
{
init_memory_pool(&pool);
const expression_t *result = read_expression(&pool, "15+54", 5);
ASSERT_NOT_NULL(result);
ASSERT_FALSE(result->is_number);
ASSERT_NOT_NULL(result->application.operands[0]);
ASSERT_TRUE(result->application.operands[0]->is_number);
ASSERT_EQUAL(15, result->application.operands[0]->number);
ASSERT_NOT_NULL(result->application.operands[1]);
ASSERT_TRUE(result->application.operands[1]->is_number);
ASSERT_EQUAL(54, result->application.operands[1]->number);
}
static void
input_6_minus_2_with_no_spaces_is_read_as_a_subtract_application(void)
{
init_memory_pool(&pool);
const expression_t *result = read_expression(&pool, "6-2", 3);
ASSERT_NOT_NULL(result);
ASSERT_FALSE(result->is_number);
ASSERT_EQUAL(OPERATOR_SUBTRACT, result->application.operator);
}
static void
input_1_plus_2_plus_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_ADD, 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();
RUN_TEST(input_1234_is_read_as_number_with_expected_value);
RUN_TEST(input_4321_is_read_as_number_with_expected_value);
RUN_TEST(input_1234_with_len_3_is_read_as_123);
RUN_TEST(operands_of_15_plus_54_are_read_as_numbers);
RUN_TEST(input_1_plus_2_with_no_spaces_is_read_as_an_add_application);
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_right_nested_application);
TESTING_END();
}