> In order to statically compile a very highly dynamic language, you really do need to do some static analysis to eliminate some of the dynamism. Or you can re

> In order to statically compile a very highly dynamic language, you really do need to do some static analysis to eliminate some of the dynamism. Or you can require the user to add type annotations, if/when he wants fast code. In SBCL (a compiler for Common Lisp): (defun count-even (array) (declare (optimize speed (safety 0))) ; <- these are the optimisation settings for this function (declare ((simple-array fixnum) array)) ; <- the argument to the function is an array of fixed sized integers (loop for x across array count (evenp x))) This compiles down to quite efficient assembly: > (disassemble 'count-even) ; disassembly for COUNT-EVEN ; Size: 65 bytes ; 05A7ABC2: BB17001020 MOV EBX, 537919511 ; no-arg-parsing entry point ; BC7: 498BF8 MOV RDI, R8 ; BCA: 31C9 XOR ECX, ECX ; BCC: 31F6 XOR ESI, ESI ; BCE: 31D2 XOR EDX, EDX ; BD0: 498B70F9 MOV RSI, [R8-7] ; BD4: 660F1F840000000000 NOP ; BDD: 0F1F00 NOP ; BE0: L0: 4839F1 CMP RCX, RSI ; BE3: 7D18 JNL L1 ; BE5: 488B5C8F01 MOV RBX, [RDI+RCX*4+1] ; BEA: 4883C102 ADD RCX, 2 ; BEE: 4883E302 AND RBX, 2 ; BF2: 4885DB TEST RBX, RBX ; BF5: 75E9 JNE L0 ; BF7: 4883C202 ADD RDX, 2 ; BFB: EBE3 JMP L0 ; BFD: L1: 488BE5 MOV RSP, RBP ; C00: F8 CLC ; C01: 5D POP RBP ; C02: C3 RET If you don't add the type annotation (the second declare form), the compiler will tell you that it can't optimise the code because of type uncertainty. Optimising a program becomes a dialogue between the user and the compiler.