Build Your Own Programming Language

Chapter 5: Syntax Trees

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 ...