From 7b0d1a74a0fc6382bfb9c382ba51f3b368b83186 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 12 May 2015 14:14:35 -0400
Subject: [PATCH] Experimenting with resolving imports on front-end

---
 Makefile                         |  8 ++++----
 cyclone.scm                      | 15 ++++++++++++++-
 examples/hello-library/hello.scm | 13 +++++--------
 trans.scm                        | 26 ++++++++++++++++++++------
 4 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/Makefile b/Makefile
index 7076cc1c..42b91108 100644
--- a/Makefile
+++ b/Makefile
@@ -42,11 +42,11 @@ test: $(TESTFILES) cyclone
 # A temporary testing directive
 .PHONY: test2
 test2: examples/hello-library/int-test/hello.c libcyclone.a
-#	./cyclone -t examples/hello-library/hello.scm
 	./cyclone -t examples/hello-library/libs/lib2.sld
-	gcc examples/hello-library/int-test/lib2.c -I. -g -c -o lib2.o
-	gcc examples/hello-library/int-test/hello.c -I. -g -c -o hello.o
-	gcc hello.o lib2.o -L. -lcyclone -lm -o hello
+	./cyclone -t examples/hello-library/hello.scm
+#	gcc examples/hello-library/int-test/lib2.c -I. -g -c -o lib2.o
+#	gcc examples/hello-library/int-test/hello.c -I. -g -c -o hello.o
+#	gcc hello.o lib2.o -L. -lcyclone -lm -o hello
 #	gcc examples/hello-library/hello.c -L. -lcyclone -lm -I. -g -o hello
 
 icyc: cyclone icyc.scm eval.scm parser.scm runtime.h
diff --git a/cyclone.scm b/cyclone.scm
index 9716eac9..21c4fe08 100644
--- a/cyclone.scm
+++ b/cyclone.scm
@@ -30,6 +30,7 @@
       (define globals '())
       (define program? #t) ;; Are we building a program or a library?
       (define imports '())
+      (define imported-vars '())
       (define lib-name '())
       (define lib-exports '())
 
@@ -51,6 +52,18 @@
          ;(error (list 'imports (cdar input-program)))
         ))
 
+      ;; Process library imports
+      ;; TODO: this may not be good enough, may need to tag library
+      ;; imports uniquely to reduce issues when the same variable
+      ;; is used by multiple libraries, and to allow renaming of imports.
+      ;; As of now, that will have to be dealt with later.
+      (trace:info "imports:")
+      (trace:info imports)
+      ;; TODO: need to get basedir from env, this is just a placeholder
+      (set! imported-vars (lib:resolve-imports imports "examples/hello-library")) ;;"."))
+      (trace:info "resolved imports:")
+      (trace:info imported-vars)
+
       ;; TODO: how to handle stdlib when compiling a library??
       ;; either need to keep track of what was actually used,
       ;; or just assume all imports were used and include them
@@ -79,7 +92,7 @@
       ; set!'s below, since all remaining phases operate on set!, not define.
       ;
       ; TODO: consider moving some of this alpha-conv logic below back into trans?
-      (set! globals (global-vars input-program))
+      (set! globals (append imported-vars (global-vars input-program)))
       (set! input-program 
         (map
           (lambda (expr)
diff --git a/examples/hello-library/hello.scm b/examples/hello-library/hello.scm
index 92b8fe89..98fc2aa8 100644
--- a/examples/hello-library/hello.scm
+++ b/examples/hello-library/hello.scm
@@ -1,12 +1,9 @@
         ; TODO: just adding temporarily until import is supported.
         ; idea is to try and see how the C code needs to change to
-        ; support libraries
-        (define lib2-hello 
-            "Hello from library #2")
-;(import ;(scheme base)
-;        (libs lib2)
-;        ;(rename (prefix (libs lib1) test-))
-;        )
-;
+(import ;(scheme base)
+        (libs lib2)
+        ;(rename (prefix (libs lib1) test-))
+        )
+
 ;(test-lib1-hello)
 (write lib2-hello)
diff --git a/trans.scm b/trans.scm
index a8af92df..ddcb2df8 100644
--- a/trans.scm
+++ b/trans.scm
@@ -1774,15 +1774,21 @@
 ;; Convert name (as list of symbols) to a mangled string
 (define (lib:name->string name)
   (apply string-append (map mangle name)))
+;; Helper function that returns an empty list as a default value
+(define (lib:result result)
+  (if result result '()))
 (define (lib:exports ast)
-  (and-let* ((code (assoc 'export (cddr ast))))
-    (cdr code)))
+  (lib:result 
+    (and-let* ((code (assoc 'export (cddr ast))))
+      (cdr code))))
 (define (lib:imports ast)
-  (and-let* ((code (assoc 'import (cddr ast))))
-    (cdr code)))
+  (lib:result
+    (and-let* ((code (assoc 'import (cddr ast))))
+      (cdr code))))
 (define (lib:body ast)
-  (and-let* ((code (assoc 'begin (cddr ast))))
-    (cdr code)))
+  (lib:result
+    (and-let* ((code (assoc 'begin (cddr ast))))
+      (cdr code))))
 ;; TODO: include, include-ci, cond-expand
 
 ;; resolve library filename from an import
@@ -1803,6 +1809,14 @@
          (exports (lib:exports (car lib))))
     (close-input-port fp)
     exports))
+;; Take a list of imports and resolve it to the imported vars
+(define (lib:resolve-imports imports basedir)
+ (apply
+   append
+   (map 
+     (lambda (import)
+       (lib:import->export-list import basedir))
+     imports)))
 
 ;; END Library section