[Ongoing] Rewrite frontend to use Flex/Bison

This is a merge of another experiment, so the changes are large:

- separated "modules" directory into frontend/backend
  - adjusted module names and moved files for this to happen
- removed modules lexer & parser
- removed all the unit tests (most were outdated)
- added Bison, flex, and C development tools to manifest.scm
- added lexer.l, a source file used by the flex utility with a functioning lexing implementation
- added parser.y, a source file used by the bison utility with a functioning parser implementation
- added node.c and node.h, which parser.y uses to construct an AST of a C source file (up to binary ops)
- added driver.c, a Guile-C interface that provides a module to scheme programs
- added a Makefile to make all of this
- added stuff to .gitignore

1 files changed, 23 insertions, 0 deletions

diff --git a/src/backend/generator/expansion.scm b/src/backend/generator/expansion.scm
new file mode 100644
index 0000000..9fe2e0a
--- /dev/null
+++ b/src/backend/generator/expansion.scm
@@ -0,0 +1,23 @@
+(define-module (backend generator expansion)
+  #:use-module (backend ast ir)
+  #:use-module (backend utils merge-instructions)
+  #:export (instrs
+            not
+            neg
+            ret))
+
+
+(define (instrs lst)
+  #f
+  (list 'instrs (cons 'list (merge-instr lst))))
+
+(define (not src dst) (unary 'not src dst))
+(define (neg src dst) (unary 'neg src dst))
+
+(define (ret src)
+  (list (list 'mov src (list 'reg "eax"))
+        (list 'ret)))
+
+(define (unary op src dst)
+  (list (list 'mov src dst)
+        (list op dst)))