2.2 Compiler for Simple

The compiler will consist of three phases: Scanner, parser and mapper-cum-code generator. The source codes and sample test data are available elsewhere.

2.2.1 Scanner

The Scanner is “hand-coded” instead of using a Scanner generator like lex or flex. We first separate out the simple language grammar in two parts – first which will be used as a specification for writing the Scanner and second, as specification for the parser. This is a kind of “division of labour” between two parts of the compiler, but it also allows the lexical aspects of a language to be separated and concentrated, so that, for example, the same language can be implemented in some other international script like Devanagari.

The Scanner-specific part, what ...

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