commit 19770b03a9faa8e2e0bf573a9417db5bfba1eac9
parent a01eba657e3146f85b516a1c05c2009c626483cc
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Thu, 17 Dec 2015 13:44:24 -0200
comments. (More explanation about kinds of expressions.)
Diffstat:
| M | lparser.h | | | 44 | +++++++++++++++++++++++++++----------------- |
1 file changed, 27 insertions(+), 17 deletions(-)
diff --git a/lparser.h b/lparser.h
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.h,v 1.73 2014/06/19 18:27:20 roberto Exp roberto $
+** $Id: lparser.h,v 1.74 2014/10/25 11:50:46 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -13,25 +13,35 @@
/*
-** Expression descriptor
+** Expression descriptor.
+** Code generation for expressions can be delayed to allow
+** optimizations; An 'expdesc' structure describes a
+** potentially-delayed expression.
*/
+/* kinds of expressions */
typedef enum {
- VVOID, /* no value */
- VNIL,
- VTRUE,
- VFALSE,
- VK, /* info = index of constant in 'k' */
- VKFLT, /* nval = numerical float value */
- VKINT, /* nval = numerical integer value */
- VNONRELOC, /* info = result register */
- VLOCAL, /* info = local register */
- VUPVAL, /* info = index of upvalue in 'upvalues' */
- VINDEXED, /* t = table register/upvalue; idx = index R/K */
- VJMP, /* info = instruction pc */
- VRELOCABLE, /* info = instruction pc */
- VCALL, /* info = instruction pc */
- VVARARG /* info = instruction pc */
+ VVOID, /* expression has no value */
+ VNIL, /* constant nil */
+ VTRUE, /* constant true */
+ VFALSE, /* constant false */
+ VK, /* constant in 'k'; info = index of constant in 'k' */
+ VKFLT, /* floating constant; nval = numerical float value */
+ VKINT, /* integer constant; nval = numerical integer value */
+ VNONRELOC, /* expression has its value in a fixed register;
+ info = result register */
+ VLOCAL, /* local variable; info = local register */
+ VUPVAL, /* upvalue; info = index of upvalue in 'upvalues' */
+ VINDEXED, /* indexed expression;
+ ind.vt = whether 't' is register or upvalue;
+ ind.t = table register or upvalue;
+ ind.idx = index as R/K */
+ VJMP, /* expression is a test/comparison;
+ info = pc of corresponding jump instruction */
+ VRELOCABLE, /* expression can put result in any register;
+ info = instruction pc */
+ VCALL, /* expression is a function call; info = instruction pc */
+ VVARARG /* vararg expression; info = instruction pc */
} expkind;
