From 03076f9edee22b14408d7ecd43168d095f9a4a3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@lysator.liu.se>
Date: Sun, 19 Jul 2020 19:32:49 +0200
Subject: Start cpp.

---
 module/vulgar/parse-cpp.scm | 373 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 373 insertions(+)
 create mode 100644 module/vulgar/parse-cpp.scm

(limited to 'module/vulgar')

diff --git a/module/vulgar/parse-cpp.scm b/module/vulgar/parse-cpp.scm
new file mode 100644
index 00000000..62d1e41a
--- /dev/null
+++ b/module/vulgar/parse-cpp.scm
@@ -0,0 +1,373 @@
+(define-module (vulgar parse-cpp)
+  :use-module (util)
+  :use-module (ice-9 popen)
+  :use-module (ice-9 rdelim)
+  :use-module (ice-9 peg)
+  :use-module (ice-9 match)
+  )
+
+
+(define (read-lines port)
+  (with-input-from-port port
+    (lambda ()
+      (let loop ((line (read-line)))
+        (if (eof-object? line)
+            '() (cons line (loop (read-line))))))))
+
+(define (parse-header header-file)
+  (map (lambda (line)
+         (let* ((symbol (string-index line #\space))
+                (value (string-index line #\space (1+ symbol))))
+           (cons (substring line (1+ symbol) value)
+                 (substring line (1+ value)))))
+   (read-lines (open-input-pipe (string-append "cpp -dM " header-file))))
+
+  #;
+  (let* (((_ key . values) (string-split line #\space)))
+    (if (char=? #\_ (string-ref key 0))
+        (loop (read-line))
+        (cons (cons key (string-join values " " 'infix))
+              (loop (read-line)))))
+
+
+
+  )
+
+
+
+;;; Lexer
+
+
+(define-peg-pattern base-8-digit body
+  (range #\0 #\7))
+
+(define-peg-pattern base-10-digit body
+  (range #\0 #\9))
+
+(define-peg-pattern base-16-digit body
+  (or (range #\0 #\9)
+      (range #\A #\F)
+      (range #\a #\f)))
+
+(define-peg-pattern base-10 all (+ base-10-digit))
+(define-peg-pattern base-8 all (and "0" (+ base-8-digit)))
+(define-peg-pattern base-16 all (and "0x" (+ base-16-digit)))
+
+(define-peg-pattern number body
+  (or base-8 base-16 base-10))
+
+(define-peg-pattern group all
+  (and (ignore "(") expr (ignore ")")))
+
+(define-peg-pattern base-8-char all
+  (and base-8-digit
+       (? base-8-digit)
+       (? base-8-digit)))
+
+(define-peg-pattern base-16-char all
+  (and (ignore "x") base-16-digit (? base-16-digit)))
+
+(define-peg-pattern escaped-char all
+  (and (ignore "\\") (or base-16-char
+                         base-8-char
+                         peg-any)))
+
+(define-peg-pattern char all
+  (and (ignore "'") (or escaped-char peg-any) (ignore "'")))
+
+;; (define-peg-pattern string body
+;;   (and "\"" (+ (or "\\\"" peg-any)) "\""))
+
+;;; Simple operators are those which can be combined with '='
+(define-peg-pattern simple-operator body
+  (or "+" "-" "*" "/" "&" "|" "^" "<<" ">>" "%"
+      "<" ">" "="))
+
+(define-peg-pattern operator all
+  (or (and simple-operator "=")
+      "&&" "||"
+      simple-operator
+      "!=" ","
+      "and" "bitand" "and_eq"
+      "or" "bitor" "or_eq"
+      "xor" "xor_eq"
+      ;; "->" "." ; special cases since can only be used with variables
+      ;; Todo Ternaries
+      ))
+
+
+;; whitespace
+(define-peg-pattern ws none
+  (or " " "	" "\n"))
+
+;; space (for when whitespace is optional)
+(define-peg-pattern sp none
+  (* ws))
+
+(define-peg-pattern safe-letter body
+  (or "_"
+      (range #\A #\Z)
+      (range #\a #\z)))
+
+(define-peg-pattern variable all
+  (and safe-letter
+       (* (or safe-letter
+              base-10-digit))))
+
+;; No further subparsing can be done.
+;; NOTE that strings are generally also in this category.
+(define-peg-pattern atom all
+  (or base-8 base-10 base-16 number char variable))
+
+;;; ++ and -- both pre and postfix
+
+(define-peg-pattern prefix-operator all
+  (or "!" "~" "*" "&" "++" "--" "+" "-"))
+
+(define-peg-pattern prefix all
+  (and prefix-operator sp expr))
+
+(define-peg-pattern postfix-operator all
+  (or "++" "--"))
+
+(define-peg-pattern postfix all
+  ;; literals can't be in-place incremented and decremented
+  ;; Make sure we don't match postfix-operator here, since
+  ;; that also gives us an infinite loop.
+  (and (or prefix infix funcall group variable) sp postfix-operator))
+
+;; 5 + 3 * 9
+;; (5 + 3) * 9
+;; 5 + (3 * 9)
+(define-peg-pattern infix all
+  ;; first case is "same" as expr, but in different order to prevent
+  ;; infinite self reference.
+  (and (or funcall group char prefix #; postfix number variable
+           ) sp operator sp expr))
+
+(define-peg-pattern funcall all
+  (and variable sp group))
+
+;;; main parser
+(define-peg-pattern expr body
+  (+ (and sp (or prefix #; postfix infix funcall group char number variable
+                 ) sp)))
+
+
+(define (lex string)
+  (peg:tree (match-pattern expr string)))
+
+
+;;; Parser
+
+
+(define (parse-lexeme-tree tree)
+  (match tree
+    ['() '()]
+
+    ;; Number constants
+    [('base-10 n) (string->number n 10)]
+    [('base-8  n) (string->number n  8)]
+    [('base-16 n) (string->number n 16)]
+
+    ;; Character literals
+    [('char ('escaped-char ('base-8-char n)))
+     (-> n (string->number 8) integer->char)]
+    [('char ('escaped-char ('base-16-char n)))
+     (-> n (string->number 16) integer->char)]
+    [('char ('escaped-char c))
+     (case (string-ref c 0)
+       ((#\a) #\alarm)
+       ((#\b) #\backspace)
+       ((#\e) #\esc)
+       ((#\f) #\page)
+       ((#\n) #\newline)
+       ((#\r) #\return)
+       ((#\t) #\tab)
+       ((#\v) #\vtab)
+       ((#\\) #\\)
+       ((#\') #\'))]
+    [('char c) (string-ref c 0)]
+
+    [('variable var) (string->symbol var)]
+    [('operator op)  (string->symbol op)]
+    [('prefix-operator op)
+     (case (string->symbol op)
+       ((*) 'dereference)
+       ((&) 'pointer)
+       ((++) 'pre-increment)
+       ((--) 'pre-decrement)
+       (else => identity))]
+    [('postfix-operator op)
+     (case (string->symbol op)
+       [(++) 'post-increment]
+       [(--) 'post-decrement]
+       [else => identity])]
+
+    ;; Parenthesis grouping
+    [('group args)
+     (parse-lexeme-tree args)]
+
+    ;; Atomic item. Used by flatten-infix
+    [('atom body)
+     (parse-lexeme-tree body)]
+
+    [('prefix op arg)
+     `(,(parse-lexeme-tree op)
+       ,(parse-lexeme-tree arg))]
+
+    [('postfix arg op)
+     `(,(parse-lexeme-tree op)
+       ,(parse-lexeme-tree arg))]
+
+    [('infix args ...)
+     (resolve-order-of-operations
+      (flatten-infix (cons 'infix args)))]
+
+    [('funcall function ('group arguments))
+     `(funcall ,(parse-lexeme-tree function)
+               ,(parse-lexeme-tree arguments))]
+
+    [bare (error "Naked literal in lex-tree. How did that get there?"
+                 bare)]))
+
+;;; TODO
+;; (f "*C++")
+;; $427 = (dereference (post-increment C))
+
+(define (group-by list item)
+  (let loop ((done '())
+             (current '())
+             (rem list))
+    (cond [(null? rem)
+           (reverse (cons (reverse current) done))]
+          [(eqv? item (car rem))
+           (loop (cons (reverse current) done)
+                 '()
+                 (cdr rem))]
+          [else
+           (loop done
+                 (cons (car rem) current)
+                 (cdr rem))])))
+
+;; https://en.wikipedia.org/wiki/Operators_in_C_and_C%2B%2B
+
+(define order-of-operations
+  (reverse
+   (apply append
+          ;; This is only for binary operations
+    `((* / %)
+      (+ -)
+      (<< >>)
+      (< <= > >=)
+      (== !=)
+      (&)
+      (^)
+      (,(symbol #\|))
+      (&&)
+      (,(symbol #\| #\|))
+      (= += -= *= /= %= <<= >>= &= ^= ,(symbol #\| #\=))
+      (,(symbol #\,))
+      ))))
+
+
+;; (f "2 + (2*2)")
+;; <unnamed port>:5967:23: In procedure resolve-order-of-operations:
+;; In procedure car: Wrong type argument in position 1 (expecting pair): ()
+
+;; Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
+
+(define* (resolve-order-of-operations
+          tree optional: (order order-of-operations))
+
+  (cond [(null? order) (car tree)]
+        [(not (list? tree)) tree]
+        [(= 1 (length tree)) (resolve-order-of-operations
+                              (car tree) order)]
+        [else
+         (let ((groups (group-by tree (car order))))
+           (cond [(= 1 (length groups))
+                  (resolve-order-of-operations
+                   (car groups) (cdr order))]
+                 [else
+                  (cons (car order)
+                        (append
+                         (map (lambda (g) (resolve-order-of-operations
+                                      g (cdr order)))
+                              groups)))]))]))
+
+;; Flatens a tree of infix triples. Stops when it should.
+(define (flatten-infix form)
+  (match form
+    [('infix left op ('infix right ...))
+     (cons* (parse-lexeme-tree left)
+            (parse-lexeme-tree op)
+            (flatten-infix (cons 'infix right)))]
+    [('infix left op right)
+     (map parse-lexeme-tree (list left op right))]
+    [other (parse-lexeme-tree other)]))
+
+
+;; scheme@(vulgar parse-cpp)> (match-pattern expr "a xorb")
+;; $10 = #<peg start: 0 end: 6 string: a xorb tree: (infix (variable a) (operator xor) (variable b))>
+
+
+(define (do-funcall function arguments)
+  (if (list? arguments)
+      (apply function arguments)
+      (function arguments)))
+
+(define-public (replace-symbols tree dict)
+  (if (not (list? tree))
+      (or (assoc-ref dict tree) tree)
+      (map (lambda (node) (replace-symbols node dict))
+           tree)))
+
+(define f (compose parse-lexeme-tree lex))
+
+;;; Right, when left simple binding
+;; direct constant (int|char)
+;; (op forms ...)
+;; (do-funcall forms ...)
+;; direct variable
+
+(define (parse-cpp-define pair)
+  (define left (f (car pair)))
+  (define right (replace-symbols
+                 (f (cdr pair))
+                 `((,(symbol #\|) . logior)
+                   (funcall . do-funcall)
+                   (&& . and)
+                   (& . logand)
+                   (== . =)
+                   (!= . (negate =))
+                   )))
+
+  (match left
+    [('funcall name ('#{,}# args ...))
+     `(define (,name ,@args)
+        ,right)]
+
+    [('funcall name arg)
+     `(define (,name ,arg)
+        ,right)]
+
+    [name `(define ,name ,right)]))
+
+;;; TODO order of these, to resolve dependencies
+(define (parse-cpp-file file)
+  ;; (map parse-cpp-define (parse-header file))
+  (map (lambda (i line) (catch #t (lambda () (parse-cpp-define line))
+                     (lambda (err caller fmt args . _) (format #t "~a ~?~%" i fmt args) #f)))
+       (iota (length (parse-header file)) 1)
+       (parse-header file)))
+
+;; (parse-cpp-file "/usr/include/termios.h")
+
+(begin
+  (define file (open-output-file "/tmp/termios.scm"))
+  (define lines (parse-cpp-file "/usr/include/termios.h"))
+
+  (for-each (lambda (line) (format file "~y" line))
+            lines)
+  (close-port file))
-- 
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