diff options
Diffstat (limited to 'manual/manual.of')
-rw-r--r-- | manual/manual.of | 139 |
1 files changed, 9 insertions, 130 deletions
diff --git a/manual/manual.of b/manual/manual.of index 6d19e251..73d25951 100644 --- a/manual/manual.of +++ b/manual/manual.of | |||
@@ -1467,7 +1467,7 @@ It has the following syntax: | |||
1467 | exp @bnfter{,} exp @bnfopt{@bnfter{,} exp} @Rw{do} block @Rw{end}} | 1467 | exp @bnfter{,} exp @bnfopt{@bnfter{,} exp} @Rw{do} block @Rw{end}} |
1468 | } | 1468 | } |
1469 | The given identifier (@bnfNter{Name}) defines the control variable, | 1469 | The given identifier (@bnfNter{Name}) defines the control variable, |
1470 | which is a new variable local to the loop body (@emph{block}). | 1470 | which is a new read-only variable local to the loop body (@emph{block}). |
1471 | 1471 | ||
1472 | The loop starts by evaluating once the three control expressions. | 1472 | The loop starts by evaluating once the three control expressions. |
1473 | Their values are called respectively | 1473 | Their values are called respectively |
@@ -1499,11 +1499,6 @@ For integer loops, | |||
1499 | the control variable never wraps around; | 1499 | the control variable never wraps around; |
1500 | instead, the loop ends in case of an overflow. | 1500 | instead, the loop ends in case of an overflow. |
1501 | 1501 | ||
1502 | You should not change the value of the control variable | ||
1503 | during the loop. | ||
1504 | If you need its value after the loop, | ||
1505 | assign it to another variable before exiting the loop. | ||
1506 | |||
1507 | } | 1502 | } |
1508 | 1503 | ||
1509 | @sect4{@title{The generic @Rw{for} loop} | 1504 | @sect4{@title{The generic @Rw{for} loop} |
@@ -1526,7 +1521,8 @@ for @rep{var_1}, @Cdots, @rep{var_n} in @rep{explist} do @rep{body} end | |||
1526 | works as follows. | 1521 | works as follows. |
1527 | 1522 | ||
1528 | The names @rep{var_i} declare loop variables local to the loop body. | 1523 | The names @rep{var_i} declare loop variables local to the loop body. |
1529 | The first of these variables is the @emph{control variable}. | 1524 | The first of these variables is the @emph{control variable}, |
1525 | which is a read-only variable. | ||
1530 | 1526 | ||
1531 | The loop starts by evaluating @rep{explist} | 1527 | The loop starts by evaluating @rep{explist} |
1532 | to produce four values: | 1528 | to produce four values: |
@@ -1550,9 +1546,6 @@ to-be-closed variable @see{to-be-closed}, | |||
1550 | which can be used to release resources when the loop ends. | 1546 | which can be used to release resources when the loop ends. |
1551 | Otherwise, it does not interfere with the loop. | 1547 | Otherwise, it does not interfere with the loop. |
1552 | 1548 | ||
1553 | You should not change the value of the control variable | ||
1554 | during the loop. | ||
1555 | |||
1556 | } | 1549 | } |
1557 | 1550 | ||
1558 | } | 1551 | } |
@@ -1586,7 +1579,8 @@ Each variable name may be postfixed by an attribute | |||
1586 | @producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}} | 1579 | @producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}} |
1587 | } | 1580 | } |
1588 | There are two possible attributes: | 1581 | There are two possible attributes: |
1589 | @id{const}, which declares a @x{constant variable}, | 1582 | @id{const}, which declares a @emph{constant} or @emph{read-only} variable, |
1583 | @index{constant variable} | ||
1590 | that is, a variable that cannot be assigned to | 1584 | that is, a variable that cannot be assigned to |
1591 | after its initialization; | 1585 | after its initialization; |
1592 | and @id{close}, which declares a to-be-closed variable @see{to-be-closed}. | 1586 | and @id{close}, which declares a to-be-closed variable @see{to-be-closed}. |
@@ -9118,7 +9112,7 @@ is a more portable solution. | |||
9118 | @simplesect{ | 9112 | @simplesect{ |
9119 | 9113 | ||
9120 | Here we list the incompatibilities that you may find when moving a program | 9114 | Here we list the incompatibilities that you may find when moving a program |
9121 | from @N{Lua 5.3} to @N{Lua 5.4}. | 9115 | from @N{Lua 5.4} to @N{Lua 5.5}. |
9122 | 9116 | ||
9123 | You can avoid some incompatibilities by compiling Lua with | 9117 | You can avoid some incompatibilities by compiling Lua with |
9124 | appropriate options (see file @id{luaconf.h}). | 9118 | appropriate options (see file @id{luaconf.h}). |
@@ -9155,51 +9149,9 @@ change between versions. | |||
9155 | @itemize{ | 9149 | @itemize{ |
9156 | 9150 | ||
9157 | @item{ | 9151 | @item{ |
9158 | The coercion of strings to numbers in | 9152 | The control variable in @Rw{for} loops are read only. |
9159 | arithmetic and bitwise operations | 9153 | If you need to change it, |
9160 | has been removed from the core language. | 9154 | declare a local variable with the same name in the loop body. |
9161 | The string library does a similar job | ||
9162 | for arithmetic (but not for bitwise) operations | ||
9163 | using the string metamethods. | ||
9164 | However, unlike in previous versions, | ||
9165 | the new implementation preserves the implicit type of the numeral | ||
9166 | in the string. | ||
9167 | For instance, the result of @T{"1" + "2"} now is an integer, | ||
9168 | not a float. | ||
9169 | } | ||
9170 | |||
9171 | @item{ | ||
9172 | Literal decimal integer constants that overflow are read as floats, | ||
9173 | instead of wrapping around. | ||
9174 | You can use hexadecimal notation for such constants if you | ||
9175 | want the old behavior | ||
9176 | (reading them as integers with wrap around). | ||
9177 | } | ||
9178 | |||
9179 | @item{ | ||
9180 | The use of the @idx{__lt} metamethod to emulate @idx{__le} | ||
9181 | has been removed. | ||
9182 | When needed, this metamethod must be explicitly defined. | ||
9183 | } | ||
9184 | |||
9185 | @item{ | ||
9186 | The semantics of the numerical @Rw{for} loop | ||
9187 | over integers changed in some details. | ||
9188 | In particular, the control variable never wraps around. | ||
9189 | } | ||
9190 | |||
9191 | @item{ | ||
9192 | A label for a @Rw{goto} cannot be declared where a label with the same | ||
9193 | name is visible, even if this other label is declared in an enclosing | ||
9194 | block. | ||
9195 | } | ||
9196 | |||
9197 | @item{ | ||
9198 | When finalizing an object, | ||
9199 | Lua does not ignore @idx{__gc} metamethods that are not functions. | ||
9200 | Any value will be called, if present. | ||
9201 | (Non-callable values will generate a warning, | ||
9202 | like any other error when calling a finalizer.) | ||
9203 | } | 9155 | } |
9204 | 9156 | ||
9205 | } | 9157 | } |
@@ -9210,39 +9162,6 @@ like any other error when calling a finalizer.) | |||
9210 | @itemize{ | 9162 | @itemize{ |
9211 | 9163 | ||
9212 | @item{ | 9164 | @item{ |
9213 | The function @Lid{print} does not call @Lid{tostring} | ||
9214 | to format its arguments; | ||
9215 | instead, it has this functionality hardwired. | ||
9216 | You should use @idx{__tostring} to modify how values are printed. | ||
9217 | } | ||
9218 | |||
9219 | @item{ | ||
9220 | The pseudo-random number generator used by the function @Lid{math.random} | ||
9221 | now starts with a somewhat random seed. | ||
9222 | Moreover, it uses a different algorithm. | ||
9223 | } | ||
9224 | |||
9225 | @item{ | ||
9226 | By default, the decoding functions in the @Lid{utf8} library | ||
9227 | do not accept surrogates as valid code points. | ||
9228 | An extra parameter in these functions makes them more permissive. | ||
9229 | } | ||
9230 | |||
9231 | @item{ | ||
9232 | The options @St{setpause} and @St{setstepmul} | ||
9233 | of the function @Lid{collectgarbage} are deprecated. | ||
9234 | You should use the new option @St{incremental} to set them. | ||
9235 | } | ||
9236 | |||
9237 | @item{ | ||
9238 | The function @Lid{io.lines} now returns four values, | ||
9239 | instead of just one. | ||
9240 | That can be a problem when it is used as the sole | ||
9241 | argument to another function that has optional parameters, | ||
9242 | such as in @T{load(io.lines(filename, "L"))}. | ||
9243 | To fix that issue, | ||
9244 | you can wrap the call into parentheses, | ||
9245 | to adjust its number of results to one. | ||
9246 | } | 9165 | } |
9247 | 9166 | ||
9248 | } | 9167 | } |
@@ -9254,46 +9173,6 @@ to adjust its number of results to one. | |||
9254 | @itemize{ | 9173 | @itemize{ |
9255 | 9174 | ||
9256 | @item{ | 9175 | @item{ |
9257 | Full userdata now has an arbitrary number of associated user values. | ||
9258 | Therefore, the functions @id{lua_newuserdata}, | ||
9259 | @id{lua_setuservalue}, and @id{lua_getuservalue} were | ||
9260 | replaced by @Lid{lua_newuserdatauv}, | ||
9261 | @Lid{lua_setiuservalue}, and @Lid{lua_getiuservalue}, | ||
9262 | which have an extra argument. | ||
9263 | |||
9264 | For compatibility, the old names still work as macros assuming | ||
9265 | one single user value. | ||
9266 | Note, however, that userdata with zero user values | ||
9267 | are more efficient memory-wise. | ||
9268 | } | ||
9269 | |||
9270 | @item{ | ||
9271 | The function @Lid{lua_resume} has an extra parameter. | ||
9272 | This out parameter returns the number of values on | ||
9273 | the top of the stack that were yielded or returned by the coroutine. | ||
9274 | (In previous versions, | ||
9275 | those values were the entire stack.) | ||
9276 | } | ||
9277 | |||
9278 | @item{ | ||
9279 | The function @Lid{lua_version} returns the version number, | ||
9280 | instead of an address of the version number. | ||
9281 | The Lua core should work correctly with libraries using their | ||
9282 | own static copies of the same core, | ||
9283 | so there is no need to check whether they are using the same | ||
9284 | address space. | ||
9285 | } | ||
9286 | |||
9287 | @item{ | ||
9288 | The constant @id{LUA_ERRGCMM} was removed. | ||
9289 | Errors in finalizers are never propagated; | ||
9290 | instead, they generate a warning. | ||
9291 | } | ||
9292 | |||
9293 | @item{ | ||
9294 | The options @idx{LUA_GCSETPAUSE} and @idx{LUA_GCSETSTEPMUL} | ||
9295 | of the function @Lid{lua_gc} are deprecated. | ||
9296 | You should use the new option @id{LUA_GCINC} to set them. | ||
9297 | } | 9176 | } |
9298 | 9177 | ||
9299 | } | 9178 | } |