Re: Compiling expressions

"James Harris" <james.harris.1@gmail.com> wrote in message
> On Dec 29 2012, 1:11 pm, James Harris <james.harri...@gmail.com> wrote:
> ...
>
>> 1. Hand-written, not the output of a parser generator.
>> 2. Efficient and without backtracking.
>> 3. Precedences (and possibly associativities) defined in tables.
>> 4. Output to be a tree structure.
>> 5. Parenthesised subexpressions allowed.
>> 6. Some operator families are *not* to associate with each other. See
>> below.
>> 7. Monadic prefix, dyadic infix and monadic postfix operators are all
>> allowed.
>> 8. Prefix and infix operators can use some same symbols (e.g. minus
>> sign).
>>
>> Infix and postfix operators use distinct symbols.
>
> ...
>
> Here is an idea for an expression parser to try to address the points
> mentioned. I am not sure if it covers all the bases yet.


<snipped>


In case anyone is later looking for some code to parse expressions I should
say that I have placed an updated copy at


    https://groups.google.com/group/comp.lang.misc/browse_frm/thread/c21bf4f4cd55f345


The most important changes were to allow for low-precedence postfix
operators (the original code here only allowed them to be highest
precedence) and add some detailed documentation.


James

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