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CS 15-212: Fundamental Structures of Computer Science II |
In the next series of lectures we put together lexical analysis, parsing, type checking, and evaluation to form the basic components of a code interpreter, which evaluates expressions directly rather than constructing an explicit translation of the code into an intermediate language, and then into machine language, as a compiler does. Our first example uses the basic grammar of arithmetic expressions, interpreting them in terms of operations over the rational numbers.