Make Nyquist support (AUD-DO)

Nyquist AUD-DO calls out to a new function that executes script commands, and returns results in a lisp string.

lib-src/libnyquist/nyquist/nyqsrc/local.c

@@ -3,6 +3,7 @@
 /* CHANGE LOG
  * --------------------------------------------------------------------
  * 28Apr03  dm  changes for portability and fix compiler warnings
+ * 12Feb18  jkc added aud-do function, that is only available in Audacity.
  */
 
 #include "xlisp.h"
@@ -53,3 +54,50 @@ void print_local_gc_info(void)
              max_sample_block_len) / 1024);
     stdputstr(buf);
 }
+
+
+
+
+/*--------------------Audacity Automation -------------------------*/
+/* These functions may later move to their own source file. */
+extern void * ExecForLisp( char * pIn );
+extern void * nyq_make_opaque_string( int size, unsigned char *src );
+
+
+void * nyq_make_opaque_string( int size, unsigned char *src ){
+    LVAL dst;
+    unsigned char * dstp;
+    dst = new_string((int)(size+2));
+    dstp = getstring(dst);
+
+    /* copy the source to the destination */
+    while (size-- > 0)
+        *dstp++ = *src++;
+    *dstp = '\0';
+
+    return (void*)dst;
+}
+
+/* xlc_aud_do -- interface to C routine aud_do */
+/**/
+LVAL xlc_aud_do(void)
+{
+// Based on string-trim...
+    unsigned char *leftp,*rightp;
+    LVAL src,dst;
+
+    /* get the string */
+    src = xlgastring();
+    xllastarg();
+
+    /* setup the string pointers */
+    leftp = getstring(src);
+    rightp = leftp + getslength(src) - 2;
+
+    // Go call my real function here...
+    dst = (LVAL)ExecForLisp( leftp );
+
+    /* return the new string */
+    return (dst);
+}
+