Recap

• correction: yacc is the original Unix tool, bison is the GNU implementation. They are both parser generators (they take a grammar written in a special DSL and produce C or C++ code implementing a parser for that grammar). The tools lex and flex are the classic Unix and GNU tools, respectively that generate a lexical analyzer: code that reads a character stream and turns it into a sequence of abstract symbols.

• Why did we spend the entire last class talking about program structure, mini-languages, and the two reasons (one cultural, one technical) the “Separate Engine and Interface” pattern is more common in the Unix world than outside it? How is this useful to you?

The most dangerous phrase in the language is, “We’ve always done it this way.” - Rear Admiral Grace Murray Hopper, USNR, (1906-1992)

Finally: make

No, really, we’ll actually get to this today.

Another make example and “easy IPC”

See /usr/share/twopipe/

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