############################################################################
#
#	Name:	skfun.icn
#
#	Title:	Scheme in Icon
#
#	Author: Bob Alexander
#
#	Date:	March 23, 1995
#
#	Description: see skeem.icn
#
############################################################################

#
# skeem -- Scheme in Icon
#

#
# Function/syntax list format
#
# Each function and syntax defined appears in a definition list which is
# processed at skeem-initialization time.  The following are the rules
# for function/syntax list entries:
#
#  -  Each entry begins with a procedure name and ends just preceding
#     the next procedure name or the end of the list.
#     - Rules regarding number of arguments:
#	 -  If an entry contains the object "oneOrMore", then it requires
#	    at least one argument.
#	 -  If an entry contains the object "twoOrMore", then it requires
#	    at least two arguments.
#	 -  If an entry contains one number N, it requires exactly N
#	    arguements.
#	 -  If an entry contains a number N followed by &null, the function
#	    requires at least N arguments.
#	 -  If an entry contains a number N followed by a number M, the
#	    function requires at least N arguments but can take no more than
#	    M arguments.
#	 -  If an entry contains no numbers but contains &null, the function
#	    can take any number of arguments.
#	 -  If an entry contains no numbers and no &null, the procedure
#	    requires exactly one argument.
#     -  If an entry contains a string, then that string is used as the
#	 function's skeem-name rather that the name calculated from its
#	 Icon procedure name.
#

procedure InitFunctions()
   every (
	 InitBasic |	      # basic syntaxes		    skbasic.icn
	 InitControl |	      # control functions	    skcontrl.icn
	 InitIO |	      # I/O functions		    skio.icn
	 InitList |	      # list & vector functions     sklist.icn
	 InitMisc |	      # misc functions		    skmisc.icn
	 InitNumber |	      # number functions	    sknumber.icn
	 InitString |	      # string and char functions   skstring.icn
	 \!InitUser())()      # user-defined functions	    skuser.icn
end

procedure DefFunction(prcList,funType)
   local item,funName,prc,minArgs,maxArgs,gotNull,special
   /funType := Function
   prc := get(prcList)
   while \prc do {
      funName := minArgs := maxArgs := gotNull := special := &null
      repeat {
	 (item := get(prcList)) | {
	    item := &null
	    break
	    }
	 if type(item) == "procedure" then break
	 if type(item) == "integer" then /minArgs | maxArgs := item
	 else if /item then gotNull := "true"
	 else if type(item) == "string" then
	    (if item == ("oneOrMore" | "twoOrMore") then special
		  else funName) := item
	 }
      if special === "oneOrMore" then minArgs := 1
      else if special === "twoOrMore" then  minArgs := 2
      else if /minArgs then
	 if \gotNull then minArgs := 0
	 else minArgs := maxArgs := 1
      else if /gotNull then
	 /maxArgs := minArgs
      /funName := ProcName(prc)
      #write("+++ ",funName,": ",image(prc),", ",image(minArgs),", ",
      #     image(maxArgs))
      DefVar(funName,funType(prc,funName,minArgs,maxArgs))
      prc := item
      }
   return
end

procedure DefSyntax(prc)
   return DefFunction(prc,Syntax)
end

procedure ProcName(prc)
   local nm
   image(prc) ? {
      tab(find(" ") + 1)
      nm := ""
      while nm ||:= tab(find("_")) do {
	 move(1)
	 nm ||:= if ="BANG" & pos(0) then "!"
	    else if ="2_" then "->"
	    else if ="P" & pos(0) then "?"
	    else "-"
	 }
      nm ||:= tab(0)
      }
   return nm
end