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############################################################################
#
# Name: skmisc.icn
#
# Title: Scheme in Icon
#
# Author: Bob Alexander
#
# Date: March 23, 1995
#
# Description: see skeem.icn
#
############################################################################
#
# skeem -- Scheme in Icon
#
# Various procedures:
#
# Booleans
# Equivalence predicates
# Symbols
# System interface
#
#
# Initialize
#
# List entries are described in skfun.icn.
#
procedure InitMisc()
DefFunction([
BOOLEAN_P,
EQUAL_P,2,
EQV_P,2,
EQ_P,2,
LOAD,
NOT,
STRING_2_SYMBOL,
SYMBOL_2_STRING,
SYMBOL_P])
return
end
#
# Booleans
#
procedure NOT(bool)
return (F === bool,T) | F
end
procedure BOOLEAN_P(x)
return (x === (T | F),T) | F
end
#
# Equivalence predicates
#
procedure EQV_P(x1,x2)
return (Eqv(x1,x2),T) | F
end
procedure EQ_P(x1,x2)
return (x1 === x2,T) | F
end
procedure EQUAL_P(x1,x2)
return (Equal(x1,x2),T) | F
end
procedure Eqv(x1,x2)
local t1,t2
t1 := type(x1)
t2 := type(x2)
return {
if not (("integer" | "real") ~== (t1 | t2)) then x1 = x2
else if not ("Char" ~== (t1 | t2)) then x1.value == x2.value
else x1 === x2
}
end
procedure Equal(x1,x2)
local t1,t2,i
return Eqv(x1,x2) | {
case (t1 := type(x1)) == (t2 := type(x2)) of {
"LLPair": Equal(LLFirst(x1),LLFirst(x2)) & Equal(LLRest(x1),LLRest(x2))
"list": {
not (every i := 1 to (*x1 == *x2) do
if not Equal(x1[i],x2[i]) then break)
}
"String": x1.value == x2.value
}
}
end
#
# Symbols
#
procedure SYMBOL_P(x)
return (SymbolP(x),T) | F
end
procedure SYMBOL_2_STRING(sym)
return String(sym)
end
procedure STRING_2_SYMBOL(s)
return s.value
end
#
# System interface
#
procedure LOAD(file)
local result,f
f := OpenFile(file,"r",LOAD) | fail
result := ReadEvalPrint(f,"quiet") | Failure
close(f)
return Failure ~=== result
end
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