feat: implement include directive with path resolution and recursive rendering for modular template composition

tests/include_test.rc

@@ -0,0 +1,27 @@
+#include "includes/math_lib.rc"
+
+int main() {
+    printf("=== Include Directive Tests ===\n");
+
+    printf("Test 1: Basic include\n");
+    int sum = add(10, 5);
+    printf("add(10, 5) = %d\n", sum);
+    printf("PASS: Included function works\n");
+
+    printf("Test 2: Multiple functions from include\n");
+    int diff = subtract(20, 7);
+    printf("subtract(20, 7) = %d\n", diff);
+    int prod = multiply(6, 4);
+    printf("multiply(6, 4) = %d\n", prod);
+    int quot = divide(15, 3);
+    printf("divide(15, 3) = %d\n", quot);
+    printf("PASS: All included functions work\n");
+
+    printf("Test 3: Using included functions in expressions\n");
+    int result = add(multiply(3, 4), subtract(10, 5));
+    printf("add(multiply(3, 4), subtract(10, 5)) = %d\n", result);
+    printf("PASS: Included functions in expressions work\n");
+
+    printf("\n=== All Include Tests Completed ===\n");
+    return 0;
+}

tests/includes/math_lib.rc

@@ -0,0 +1,18 @@
+int add(int a, int b) {
+    return a + b;
+}
+
+int subtract(int a, int b) {
+    return a - b;
+}
+
+int multiply(int a, int b) {
+    return a * b;
+}
+
+int divide(int a, int b) {
+    if (b == 0) {
+        return 0;
+    }
+    return a / b;
+}

tests/includes/string_lib.rc

@@ -0,0 +1,19 @@
+int string_length(char *s) {
+    return strlen(s);
+}
+
+char* string_upper(char *s) {
+    return upper(s);
+}
+
+char* string_lower(char *s) {
+    return lower(s);
+}
+
+int string_contains(char *haystack, char *needle) {
+    int pos = strpos(haystack, needle);
+    if (pos >= 0) {
+        return 1;
+    }
+    return 0;
+}

tests/includes/utils.rc

@@ -0,0 +1,14 @@
+#include "math_lib.rc"
+#include "string_lib.rc"
+
+int is_even(int n) {
+    int half = divide(n, 2);
+    return multiply(half, 2) == n;
+}
+
+int is_odd(int n) {
+    if (is_even(n)) {
+        return 0;
+    }
+    return 1;
+}

tests/nested_include_test.rc

@@ -0,0 +1,22 @@
+#include "includes/utils.rc"
+
+int main() {
+    printf("=== Nested Include Tests ===\n");
+
+    printf("Test 1: Functions from nested includes\n");
+    int sum = add(5, 3);
+    printf("add(5, 3) = %d\n", sum);
+    printf("PASS: Functions from first-level include work\n");
+
+    printf("Test 2: Utility functions using nested includes\n");
+    if (is_even(10)) {
+        printf("is_even(10) = true\n");
+    }
+    if (is_odd(7)) {
+        printf("is_odd(7) = true\n");
+    }
+    printf("PASS: Utility functions using nested includes work\n");
+
+    printf("\n=== All Nested Include Tests Completed ===\n");
+    return 0;
+}