Issue #412 - Fix expand within a cond-expand

Allow these dependencies to be recognized by Cyclone.

CHANGELOG.md

@@ -5,6 +5,9 @@
 Bug Fixes
 
 - The compiler now displays a helpful error message to the user when compilation of a program fails due to an error building a dependent library.
+- Enhanced `cond-expand` support in a library declaration to
+  - Properly handle cases where there is more than one `cond-expand` sub-expression. EG: two `begin` expressions, a `begin` / `import`, etc.
+  - Properly handle the case where `export` is defined by `cond-expand`. Previously such exports would not be recognized by code importing the library.
 
 ## 0.21 - September 17, 2020
 

cyclone.scm

@@ -182,7 +182,7 @@
       (report:elapsed "imports:")
       (trace:info "imports:")
       (trace:info imports)
-      (set! imported-vars (lib:imports->idb imports append-dirs prepend-dirs))
+      (set! imported-vars (lib:imports->idb imports append-dirs prepend-dirs (base-expander)))
       (report:elapsed "resolved imports:")
       (trace:info "resolved imports:")
       (trace:info imported-vars)
@@ -245,7 +245,7 @@
             (set! imports (append imports (car program:imports/code)))
             (trace:info "imports:")
             (trace:info imports)
-            (set! imported-vars (lib:imports->idb imports append-dirs prepend-dirs))
+            (set! imported-vars (lib:imports->idb imports append-dirs prepend-dirs (base-expander)))
             (report:elapsed "resolved imports:")
             (trace:info "resolved imports:")
             (trace:info imported-vars)

examples/game-of-life/example/grid.sld

@@ -1,7 +1,10 @@
 ; Example from draft 6 of R7RS
 (define-library (example grid)
+  (cond-expand
+   (cyclone
     (export make rows cols ref each
             put!) ;(rename put! set!))
+   ))
     (import (scheme base))
     (begin
       ;; Create an NxM grid.

examples/game-of-life/example/life.sld

@@ -1,21 +1,17 @@
 (define-library (example life)
-  (import (except (scheme base) set!)
-         ; (scheme write)
-         ; (example grid)
-          )
+  (import (except (scheme base) set!))
   (cond-expand
     (cyclone
      (import (scheme write))
-;     ))
-;  (cond-expand
-;    (cyclone
      (import (example grid))
-           ))
+     
+     ))
            
-  ;(cond-expand
-  ;  (cyclone
+  (cond-expand
+    (cyclone
   (export life)
-  ;))
+  ))
+
   (cond-expand
     (cyclone
     (begin

scheme/cyclone/libraries.sld

@@ -440,12 +440,15 @@
     " "))
 
 ;; Read export list for a given import
-(define (lib:import->export-list import append-dirs prepend-dirs)
+(define (lib:import->export-list import append-dirs prepend-dirs expander)
   (let* ((lib-name (lib:import->library-name import))
          (dir (string-append (lib:import->filename lib-name ".sld" append-dirs prepend-dirs)))
          (fp (open-input-file dir))
          (lib (read-all fp))
-         (exports (lib:exports (car lib))))
+         (lib* (if expander
+                   (list (lib:cond-expand (car lib) expander))
+                   lib))
+         (exports (lib:exports (car lib*))))
     (close-input-port fp)
     (lib:import-set/exports->imports import exports)))
 
@@ -551,7 +554,7 @@
 ;;
 ;; TODO: convert this to use a hashtable. Initially a-lists
 ;; will be used to prove out the concept, but this is inefficient
-(define (lib:imports->idb imports append-dirs prepend-dirs)
+(define (lib:imports->idb imports append-dirs prepend-dirs expander)
  (apply
    append
    (map 
@@ -563,7 +566,7 @@
               (cons id lib-name)
               ids))
           '()
-           (lib:import->export-list import-set append-dirs prepend-dirs))))
+           (lib:import->export-list import-set append-dirs prepend-dirs expander))))
      (map lib:list->import-set imports))))
 
 ;; Convert from the import DB to a list of identifiers that are imported.