Initial data commit

Task/Call-a-foreign-language-function/Lisaac/call-a-foreign-language-function.lisaac

@@ -0,0 +1,24 @@
+Section Header
+
++ name := TEST_C_INTERFACE;
+
+// this will be inserted in front of the program
+- external := `#include <string.h>`;
+
+Section Public
+
+- main <- (
+  + s : STRING_CONSTANT;
+  + p : NATIVE_ARRAY[CHARACTER];
+
+  s := "Hello World!";
+  p := s.to_external;
+  // this will be inserted in-place
+  // use `expr`:type to tell Lisaac what's the type of the external expression
+  p := `strdup(@p)` : NATIVE_ARRAY[CHARACTER];
+  s.print;
+  '='.print;
+  p.println;
+  // this will also be inserted in-place, expression type disregarded
+  `free(@p)`;
+);