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authorPhilipp Janda <siffiejoe@gmx.net>2016-02-21 12:28:13 +0100
committerPhilipp Janda <siffiejoe@gmx.net>2016-02-21 12:28:13 +0100
commit7cab8a5006da807d83f427217e2158079bb78145 (patch)
tree8d55377133839458dba7ff55b494146ab667e31d
parent7c1df8a7cd4271309160abfd28fb8011a3fee46f (diff)
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Update comment in except.h
-rw-r--r--src/except.h23
1 files changed, 14 insertions, 9 deletions
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 @@
9* error checking was taking a substantial amount of the coding. These 9* error checking was taking a substantial amount of the coding. These
10* function greatly simplify the task of checking errors. 10* function greatly simplify the task of checking errors.
11* 11*
12* The main idea is that functions should return nil as its first return 12* The main idea is that functions should return nil as their first return
13* value when it finds an error, and return an error message (or value) 13* values when they find an error, and return an error message (or value)
14* following nil. In case of success, as long as the first value is not nil, 14* following nil. In case of success, as long as the first value is not nil,
15* the other values don't matter. 15* the other values don't matter.
16* 16*
17* The idea is to nest function calls with the "try" function. This function 17* The idea is to nest function calls with the "try" function. This function
18* checks the first value, and calls "error" on the second if the first is 18* checks the first value, and, if it's falsy, wraps the second value in a
19* nil. Otherwise, it returns all values it received. 19* table with metatable and calls "error" on it. Otherwise, it returns all
20* values it received. Basically, it works like the Lua "assert" function,
21* but it creates errors targeted specifically at "protect".
20* 22*
21* The protect function returns a new function that behaves exactly like the 23* The "newtry" function is a factory for "try" functions that call a
22* function it receives, but the new function doesn't throw exceptions: it 24* finalizer in protected mode before calling "error".
23* returns nil followed by the error message instead.
24* 25*
25* With these two function, it's easy to write functions that throw 26* The "protect" function returns a new function that behaves exactly like
26* exceptions on error, but that don't interrupt the user script. 27* the function it receives, but the new function catches exceptions thrown
28* by "try" functions and returns nil followed by the error message instead.
29*
30* With these three functions, it's easy to write functions that throw
31* exceptions on error, but that don't interrupt the user script.
27\*=========================================================================*/ 32\*=========================================================================*/
28 33
29#include "lua.h" 34#include "lua.h"