2017-11-13 03:24:33 +01:00
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Most words in RETRO have a stack comment. These look like:
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(-)
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(nn-n)
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As with all comments, a stack comment begins with ( and should end with
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2017-11-15 02:38:42 +01:00
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a ). There are two parts to the comment. On the left side of the - is
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2017-11-13 03:24:33 +01:00
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what the word *consumes*. On the right is what it *leaves*.
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RETRO uses a short notation, with one character per value taken or left.
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In general, the following symbols represent certain types of values.
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b, n, m, o, x, y, z are generic numeric values
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s represents a string
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v represents a variable
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p, a represent pointers
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q represents a quotation
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d represents a dictionary header
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f represents a `TRUE` or `FALSE` flag.
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In the case of something like: (xyz-m)
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RETRO expects z to be on the top of the stack, with y below it and x below
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the y value. And after execution, a single value (m) will be left on the
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stack.
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Words with no stack effect have a comment of (-)
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