[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- removed all the unit tests (most were outdated)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

2 files changed, 0 insertions, 56 deletions

diff --git a/src/modules/emitter/driver.scm b/src/modules/emitter/driver.scm
deleted file mode 100644
index 7ce8517..0000000
--- a/src/modules/emitter/driver.scm
+++ /dev/null
@@ -1,6 +0,0 @@
-(define-module (emitter driver)
-  #:export (assembly->string))
-
-
-(define (assembly->string n)
-  (eval n (resolve-module '(emitter traverse))))
diff --git a/src/modules/emitter/traverse.scm b/src/modules/emitter/traverse.scm
deleted file mode 100644
index 6c0c19d..0000000
--- a/src/modules/emitter/traverse.scm
+++ /dev/null
@@ -1,50 +0,0 @@
-(define-module (emitter traverse)
-  #:export (prog
-            subrout
-            instr
-            allocate
-            mov
-            ret
-            neg
-            not
-            allocate
-            reg
-            stack
-            imm))
-
-
-(define (prog srout)
-  (string-append/shared srout ".section .note.GNU-stack,\"\",@progbits\n"))
-
-(define (srout label instrs)
-  (format #f "    .globl ~a
-~a:
-\tpushq\t%rbp
-\tmovq\t%rsp, %rbp
-~a" label label (apply string-append/shared instrs)))
-
-(define (mov src dst)
-  (format #f "\tmovl\t~a, ~a\n" src dst))
-
-(define (ret)
-  "\tmovq\t%rbp, %rsp
-\tpopq\t%rbp
-\tret\n")
-
-(define (neg dst)
-  (format #f "\tnegl\t~a\n" dst))
-
-(define (not dst)
-  (format #f "\tnotl\t~a\n" dst))
-
-(define (alloc size)
-  (format #f "\tsubq\t$~a, %rsp\n" size))
-
-(define (reg r)
-  (format #f "%~a" r))
-
-(define (stack loc)
-  (format #f "~a(%rbp)" loc))
-
-(define (imm int)
-  (format #f "$~a" int))