Syntax Trees

The preceding two chapters covered lexical and syntax analysis, the first two phases of a compiler. Next, we will need to perform semantic analysis and code generation, but those phases will need some information to work from. The parser we constructed in the last chapter can detect and report syntax errors, which is a big, important job. When there is no syntax error, you need to build a data structure during parsing that represents the whole program logically. This data structure is based on how the different tokens and larger pieces of the program are grouped together. A syntax tree is a tree data structure that records the branching structure of the grammar rules used by the parsing algorithm to check the syntax of an input source file. A branch occurs whenever two or more symbols are grouped together on the right-hand side of a grammar rule to build a non-terminal symbol. This chapter will show you how to build syntax trees, which are the central data structures...