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@@ -1,10 +1,4 @@
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____ ____ _ _____ _____
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| _ \| _ \ / \ | ___|_ _|
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| | | | |_) | / A \ | |_ | |
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| |_| | _ < / ___ \| _| | |
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|____/|_| \_\_/ \_\_| |_|
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--------------------------------------------------
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--------------------------------------------------
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Joypy
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@@ -15,7 +9,7 @@
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--------------------------------------------------
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Copyright © 2014, 2015, 2017 Simon Forman
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Copyright © 2014, 2015, 2017, 2018 Simon Forman
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This file is part of Joypy
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@@ -41,18 +35,9 @@ Joy is a programming language created by Manfred von Thun that is easy to
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use and understand and has many other nice properties. This Python
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package implements an interpreter for a dialect of Joy that attempts to
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stay very close to the spirit of Joy but does not precisely match the
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behaviour of the original version(s) written in C.
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The main difference between Joypy and the originals, other than being
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written in Python, is that it works by the "Continuation-Passing Style".
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In Joy, control-flow is done by combinators that expect quoted programs
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on the stack and execute them in various ways. In Joypy they work by
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changing the pending expression that the interpreter is about to execute.
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In concrete terms, the combinators could work by making recursive calls
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to the interpreter and all intermediate state would be held in the call
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stack of the implementation language, in this Joypy implementation they
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work instead by changing the pending expression and intermediate state
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is put there.
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behaviour of the original version(s) written in C. The main difference
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between Joypy and the originals, other than being written in Python, is
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that it works by the "Continuation-Passing Style".
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As I study Joy I find that it is very aptly named. It is clear, concise,
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and ameniable to advanced techniques for constructing bug-free software.
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@@ -125,9 +110,15 @@ are called "combinators", which accept quoted programs on the stack and
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run them in various ways. These combinators factor specific patterns
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that provide the effect of control-flow in other languages (such as ifte
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which is like if..then..else..) Combinators receive the current
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expession in addition to the stack and return the next expression. As
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mentioned above, the combinators in Joypy work by changing the pending
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expression before returning it.
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expession in addition to the stack and return the next expression.
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In Joy control-flow is done by combinators that expect quoted programs
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on the stack and execute them in various ways. In Joypy they work by
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changing the pending expression that the interpreter is about to execute.
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In concrete terms, the combinators could work by making recursive calls
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to the interpreter and all intermediate state would be held in the call
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stack of the implementation language, in this Joypy implementation they
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work instead by changing the pending expression and intermediate state
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is put there.
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In general, where otherwise unspecified, the semantics of Joypy are that
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of the underlying Python. That means, for example, that integers are
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Simon Forman