Breakpoint debugging method for LR(k) grammar random grammar position

Abstract

This invention relates to the break point debug method in the LR(k) random grammar position, its steps is: Defines language LR(k) grammar or LR(k) grammar subclass grammar G; Inserts the break point in the corresponding grammar position; Inspects each break point, if this break point establishes in some grammar position right middle of the production pattern, then adds the useless non-end mark, thus obtains new grammar G'; to generate the grammar G' analytical statement; to calculate the type of each break point; to analysis the input string, until meets a reduction operation, inspects this position whether corresponds a break point, if it is, then adopts the following: To the effective break point, suspends the parsing process, demonstrates the current analysis status messages; To the invalid break point, neglects this break point, continues the parsing process; To indefinite break point, then neglects or joints with current input string and the position the break point established, further judges this position whether effective or not, if this position of the current input string is effective, presses effective break point position processing, if this position is invalid, then neglects this position, continues the parsing process. This invention obviously increases the break point number which may track and debug, may track the fine grain grammar ingredient, helps the user to carry on the grammar debugging well, and reduces the development difficulty of analyzer.

Description

technical field [0001] The invention relates to a grammar breakpoint debugging technology, and proposes a breakpoint debugging method for an arbitrary grammatical position in an LR(k) grammar, which can significantly increase the number of breakpoints that can be tracked and debugged, and helps users better perform grammar debugging. Background technique [0002] Parser generators are widely used in the construction of parsers and compiler front ends, and more and more developers use automatic parser generation tools to generate parsers or compiler front ends. [0003] Unlike experts in the field of compilation, these ordinary developers are often not familiar with analysis theory, and they do not often develop such analysis tools. For such developers, good grammar debugging support is indispensable, which can effectively reduce the complexity of analyzer development and improve development efficiency. Even for compilation experts, good grammar debugging support can help th...

AI Technical Summary

Problems solved by technology

First of all, this method modifies the original grammar and damages the readability of the grammar; second, it adds additional processing burden to the user; third, these useless non-terminals are not part of the original grammar in nature, so after debugging Finally, they must be deleted from the grammar. In this way, every time the user sets a breakpoint, he must manually add a useless non-terminal symbol, and he has to delete it after debugging, which brings great inconvenience to the user's debugging; Finally, adding useless nonterminals to an LR(k) grammar may introduce new parsing conflicts, causing the changed grammar to no longer be an LR(k) grammar, causing the parsing process to fail

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