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Recursive descent parser generator (view source)

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{{draft task}}
 
Write a recursive descent parser generator that takes inputa indescription theof followinga formatgrammar as input and outputs the source code for a parser in the same language as the generator. (So a generator written in C++ would output C++ source code for the parser.) You can assume that all of the rules have been preprocessed into a form suitable for the construction of a recursive descent parser. See here for more details: http://www.cs.engr.uky.edu/~lewis/essays/compilers/rec-des.html
 
Example grammar:
Input format:
<pre>
plus \+
times \*
var [a-z]+
 
!! start -> expr start2
...
 
!! start2 -> plus start2
 
!! start2 -> expr
 
!! expr -> var expr2
 
!! expr2 -> times expr2
 
!! expr2 -> var
</pre>
 
Use the parser generator to build a parser that takes arithmetic expressions and turns them in to three address code. The resulting parser should take this (or something similar) as input:
The first section contains the token definitions. Each line contains the name of a token followed by a regular expression. If your language does not have support for regular expressions, you can use something simpler, but make a note of the details. Tokens are to be matched greedily in the order given. The token section ends with a blank line.
<pre>
(one + two) * three - four * five
123 + 321
</pre>
 
And generate this (or something similar) as output:
The second section contains the production rules. Each rule consists of a non-terminal symbol and [more work needs to be done on this part of the task]. You can assume that all of the rules have been preprocessed into a form suitable for the construction of a recursive descent parser. See here for more details: http://www.cs.engr.uky.edu/~lewis/essays/compilers/rec-des.html
<pre>
_0001 = one + two
_0002 = _0001 * three
_0003 = four * five
_0004 = _0002 - _0003
_0005 = 123 + 321
</pre>
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