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(define-module (c parse)
:use-module (hnh util)
:use-module (srfi srfi-1)
:use-module (ice-9 match)
:export (parse-lexeme-tree))
;;; Rename this
(define (perms set)
(concatenate
(map (lambda (key)
(map (lambda (o) (cons key o))
(delete key set)))
set)))
(define (symbol-concat pair)
(cond [(null? (car pair)) (cdr pair)]
[(null? (cdr pair)) (car pair)]
[else (symbol-append (car pair) (cdr pair))]))
(define (parse-integer-suffix str)
(define valid-sequences
(delete 'dummy
(lset-union eq? '(dummy)
(map symbol-concat (perms '(() U L)))
(map symbol-concat (perms '(() U LL))))))
;; => (LLU ULL LL LU UL L U)
(aif (memv (string->symbol (string-upcase str))
valid-sequences)
(case (car it)
[(LLU ULL) '(unsigned long-long)]
[(LU UL) '(unsigned long)]
[(LL) '(long-long)]
[(L) '(long)]
[(U) '(unsigned)])
(scm-error 'c-parse-error "parse-integer-suffix"
"Invalid integer suffix ~s"
(list str) #f)))
(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)]
[('integer n ('integer-suffix suffix))
`(as-type
,(parse-integer-suffix suffix)
,(parse-lexeme-tree n))
]
[('integer n)
(parse-lexeme-tree n)]
;; Character literals, stored as raw integers
;; so mathematical operations keep working on them.
[('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))
(char->integer
(case (string-ref c 0)
((#\a) #\alarm)
((#\b) #\backspace)
((#\e) #\esc)
((#\f) #\page)
((#\n) #\newline)
((#\r) #\return)
((#\t) #\tab)
((#\v) #\vtab)
((#\\) #\\)
((#\') #\')))]
[('char c) (char->integer (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 (scm-error 'c-parse-error
"parse-lexeme-tree"
"Naked literal in lex-tree: ~s"
(list bare)
#f)]))
;; https://en.wikipedia.org/wiki/Operators_in_C_and_C%2B%2B
(define order-of-operations
(reverse
(concatenate
;; This is only for binary operations
`((-> ,(symbol #\.))
(* / %)
(+ -)
(<< >>)
(< <= > >=)
(== !=)
(&)
(^)
(,(symbol #\|))
(&&)
(,(symbol #\| #\|))
(= += -= *= /= %= <<= >>= &= ^= ,(symbol #\| #\=))
(,(symbol #\,))
))))
(define (mark-other form)
(if (list? form) (cons '*other* form) form))
(define* (resolve-order-of-operations
tree optional: (order order-of-operations))
(if (null? order)
(car tree)
(match tree
[('*other* body ...) body]
[(form) (resolve-order-of-operations form order)]
[(forms ...)
(match (split-by forms (car order))
[(group) (resolve-order-of-operations group (cdr order))]
[groups
(cons (car order)
(map (lambda (form) (resolve-order-of-operations
form order-of-operations))
groups))])]
[a a])))
;; Flatens a tree of infix triples. Stops when it should.
;; (parenthesis, function calls, ...)
(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)
(list (mark-other (parse-lexeme-tree left))
(parse-lexeme-tree op)
(mark-other (parse-lexeme-tree right)))]
[other (scm-error 'c-parse-error
"flatten-infix"
"Not an infix tree ~a"
(list other)
#f)]))
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