| "Lisps fall down on writing performant code easily" I disagree. I would say it is actually easier to write performant code in lisps than in other languages. In languages with traditional syntax (ie. not homoiconic) it is usually tradeoff between performance and readability. As soon as you try to maximise performance, the program starts becoming unreadable. In lisps, on the other hand, due to how you can have full control over every aspect of translation between notation and generated code it is much easier to write programs that don't hurt performance just because you want nice notation or DSL. As an example, take printf. This function makes it easier to format strings and is available in many programming languages. printf("%d", 7) If no special compiler optimization is used (ie. compiler having hardcoded optimization just for printf) this results in code that will have to parse "%d" every time just to figure out, every time, it needs to take next argument and output it as integer. On the other hand typical Common Lisp format macro looks very similarly: (format t "~d" 7) but you, as an author of a macro, have option to figure out that the format is an immutable string, so you can, at the compile time, replace call to format with an equivalent call to a simpler function that will take integer as an argument and immediately print it. This way you don't have to parse the format string every time and you don't have to pay for an extra stack frame as the expanded form of the macro takes place of the macro invocation. For another example take a look at Peter Seibel's Practical Common Lisp chapter on parsing binary files (http://www.gigamonkeys.com/book/practical-parsing-binary-fil...) This chapter shows a system of macros that take very high level of description of binary data structures and generates efficient code to parse, access parsed data and serialize it to the binary format. In a typical language the requirement to have flexible description of the messages would likely result in a compromised performance. This is why so many "high performance" solution involve some variant of code generation but at the cost of additional complexity. |