util  Diff

Differences From Artifact [58b3a515c7]:

• File sexpc/example.cse — part of check-in [520b38deac] at 2019-07-23 12:32:27 on branch trunk — add sexcp (user: lexi, size: 1649) [annotate] [blame] [check-ins using]

To Artifact [d3af63ab24]:

• File sexpc/example.cse — part of check-in [844294c3a4] at 2019-07-24 22:36:50 on branch trunk — add support for conditionals, array indexing, and reference-taking (user: lexi, size: 1825) [annotate] [blame] [check-ins using]

    14     14      ; (@ … ) introduces a block of Scheme code that
    15     15      ; is evaluated in the program's environment, but
    16     16      ; whose value is silently ignored. this makes it
    17     17      ; good for defining globals you intend to use
    18     18      ; later in the program with (* … ) or (= … )
    19     19      ; blocks - see the paragraph below
    20     20      (define (sayl str)
    21         -	 `(add-> total (call write 1
           21  +	  `(add-> total (call write 1
    22     22   	  ; the return value of a scheme expression will
    23     23   	  ; be evaluated just like any other expression
    24     24   	  ; and transformed into C code, so we can rely
    25     25   	  ; on existing syntax instead of haven't to
    26     26   	  ; generate raw strings of C
    27     27   			,(string-append str "\\n")
    28     28   			,(+ 1 (string-length str))))))
    29     29   
    30     30   (decl sayhello ((ptr char) → int))
           31  +(decl usage (() => ()))
    31     32   (def (total size_t) 0)
    32     33   
    33     34   (def (main int (argc int) (argv (array (ptr char))))
    34         -	 (ret (call sayhello "dumbass")))
           35  +	 (def (voidptr (ptr ())) (cast (ptr ()) argv))
           36  +	 (cond ((neq argc 2) (call usage))
           37  +		   (else (call sayhello (idx argv 1))))) 
    35     38   
    36     39   (def (sayhello int (name (ptr char)))
    37     40   	 (* sayl "hello…")
    38     41   	 ; a list prefixed with * indicates that it 
    39     42   	 ; should be evaluated as a scheme expression
    40     43   	 ; and its result then processed, instead of
    41     44   	 ; being processed directly like (call) or
................................................................................
    42     45   	 ; (def). scheme expressions may be inserted
    43     46   	 ; anywhere a normal sexpc expression can. or
    44     47   	 ; we could instead write (= (sayl "hello…"))
    45     48   	 ; to accomplish the same effect; (= … ) is
    46     49   	 ; really just shorthand for (* begin … )
    47     50   
    48     51   	 (call write 1 name (call strlen name))
    49         -	 (ret total)
    50         -)
           52  +	 (ret total))
           53  +
           54  +(def (usage void ())
           55  +	 (* sayl "usage: example <name>"))
           56  +