[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- removed all the unit tests (most were outdated)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, 0 insertions, 35 deletions

diff --git a/src/modules/parser/driver.scm b/src/modules/parser/driver.scm
deleted file mode 100644
index e464a7a..0000000
--- a/src/modules/parser/driver.scm
+++ /dev/null
@@ -1,35 +0,0 @@
-(define-module (parser driver)
-  #:use-module (ice-9 match)
-  #:export (tokens->ast))
-
-
-(define (die)
-  (error "syntax error"))
-
-(define (tokens->ast tokens)
-  (match tokens
-    ((func ...)
-     (list 'prog (function func)))
-    (_ (die))))
-
-(define (function tokens)
-  (match tokens
-    (('int (? string? id) 'left-paren 'void 'right-paren 'open-brace stmt ... 'close-brace)
-     (list 'func id (statement stmt)))
-    (_ (die))))
-
-(define (statement tokens)
-  (match tokens
-    (('return expr ... 'semi-colon)
-     (list 'stmt (expression expr)))
-    (_ (die))))
-
-(define (expression tokens)
-  (match tokens
-    (((? integer? int))
-     (list 'const int))
-    (((or 'neg 'not) expr ...)
-     (list 'expr (car tokens) (expression expr)))
-    (('left-paren expr ... 'right-paren)
-     (expression expr))
-    (_ (die))))