问Io语言解释器和文件执行之间的不同行为

EN

## Executing nand.io
##########################
OperatorTable addOperator("nand", 10)
true nand := method(bool, if(bool, false, true))
false nand := method(bool, true)

true nand false println        # => false
true nand true println         # => true
false nand false println       # => false
false nand true println        # => true

# Why does this print 'true' (it should be 'false')?
(true nand true) println      # => true

# I noticed that the argument to nand is always printed
true nand "not" println        # => not
true nand "what" println       # => what
false nand "I" println         # => I
false nand "expected" println  # => expected

# Another sanity check. I thought this might have to do with println behaving
# oddly, but this conditional really does return true
if(true nand true, "This should not print" println, "This should print" println)
# => This should not print

# More unexpected behavior
false nand := method(arg, "foo")
false nand "bar" println       # => "bar"

true nand := method(arg, "foo")
true nand "bar" println        # => "bar"

false nand := "Why is this not returned?"
false nand "aaaaahhhh" println # => "aaaaahhhh"



## Ran in the io interpreter
###############################
OperatorTable addOperator("nand", 10)
true nand := method(bool, if(bool, false, true))
false nand := method(bool, true)

# Same as file execution when sent to println
true nand false println   # => false
true nand true println    # => true
false nand false println  # => false
false nand true println   # => true

# It acually does what's expected here
true nand false           # => true
true nand true            # => false    -- It works here!!!
false nand false          # => true
false nand true           # => true

if(true nand true, "This should not print" println, "This should print" println)
# => This should print