diff --git a/src/except.h b/src/except.h index 1e7a245..2497c05 100644 --- a/src/except.h +++ b/src/except.h @@ -9,21 +9,26 @@ * error checking was taking a substantial amount of the coding. These * function greatly simplify the task of checking errors. * -* The main idea is that functions should return nil as its first return -* value when it finds an error, and return an error message (or value) +* The main idea is that functions should return nil as their first return +* values when they find an error, and return an error message (or value) * following nil. In case of success, as long as the first value is not nil, * the other values don't matter. * * The idea is to nest function calls with the "try" function. This function -* checks the first value, and calls "error" on the second if the first is -* nil. Otherwise, it returns all values it received. +* checks the first value, and, if it's falsy, wraps the second value in a +* table with metatable and calls "error" on it. Otherwise, it returns all +* values it received. Basically, it works like the Lua "assert" function, +* but it creates errors targeted specifically at "protect". * -* The protect function returns a new function that behaves exactly like the -* function it receives, but the new function doesn't throw exceptions: it -* returns nil followed by the error message instead. +* The "newtry" function is a factory for "try" functions that call a +* finalizer in protected mode before calling "error". * -* With these two function, it's easy to write functions that throw -* exceptions on error, but that don't interrupt the user script. +* The "protect" function returns a new function that behaves exactly like +* the function it receives, but the new function catches exceptions thrown +* by "try" functions and returns nil followed by the error message instead. +* +* With these three functions, it's easy to write functions that throw +* exceptions on error, but that don't interrupt the user script. \*=========================================================================*/ #include "lua.h"