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| author | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2022-12-20 13:24:43 -0300 |
|---|---|---|
| committer | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2022-12-20 13:24:43 -0300 |
| commit | 540d8052265776451bb9f0ab4dee4ec860563cbe (patch) | |
| tree | 697f573e601d7eb5f1b5fac4026e3f9505ae8ddb /manual | |
| parent | 7d6a97e42bc3328b9c5ec1dabbd7e280e81c3efd (diff) | |
| download | lua-540d8052265776451bb9f0ab4dee4ec860563cbe.tar.gz lua-540d8052265776451bb9f0ab4dee4ec860563cbe.tar.bz2 lua-540d8052265776451bb9f0ab4dee4ec860563cbe.zip | |
Towards Lua 5.5
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/manual.of | 123 |
1 files changed, 3 insertions, 120 deletions
diff --git a/manual/manual.of b/manual/manual.of index 6d19e251..416622c1 100644 --- a/manual/manual.of +++ b/manual/manual.of | |||
| @@ -1586,7 +1586,8 @@ Each variable name may be postfixed by an attribute | |||
| 1586 | @producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}} | 1586 | @producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}} |
| 1587 | } | 1587 | } |
| 1588 | There are two possible attributes: | 1588 | There are two possible attributes: |
| 1589 | @id{const}, which declares a @x{constant variable}, | 1589 | @id{const}, which declares a @emph{constant} or @emph{read-only} variable, |
| 1590 | @index{constant variable} | ||
| 1590 | that is, a variable that cannot be assigned to | 1591 | that is, a variable that cannot be assigned to |
| 1591 | after its initialization; | 1592 | after its initialization; |
| 1592 | and @id{close}, which declares a to-be-closed variable @see{to-be-closed}. | 1593 | and @id{close}, which declares a to-be-closed variable @see{to-be-closed}. |
| @@ -9118,7 +9119,7 @@ is a more portable solution. | |||
| 9118 | @simplesect{ | 9119 | @simplesect{ |
| 9119 | 9120 | ||
| 9120 | Here we list the incompatibilities that you may find when moving a program | 9121 | Here we list the incompatibilities that you may find when moving a program |
| 9121 | from @N{Lua 5.3} to @N{Lua 5.4}. | 9122 | from @N{Lua 5.4} to @N{Lua 5.5}. |
| 9122 | 9123 | ||
| 9123 | You can avoid some incompatibilities by compiling Lua with | 9124 | You can avoid some incompatibilities by compiling Lua with |
| 9124 | appropriate options (see file @id{luaconf.h}). | 9125 | appropriate options (see file @id{luaconf.h}). |
| @@ -9155,51 +9156,6 @@ change between versions. | |||
| 9155 | @itemize{ | 9156 | @itemize{ |
| 9156 | 9157 | ||
| 9157 | @item{ | 9158 | @item{ |
| 9158 | The coercion of strings to numbers in | ||
| 9159 | arithmetic and bitwise operations | ||
| 9160 | has been removed from the core language. | ||
| 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 | } | 9159 | } |
| 9204 | 9160 | ||
| 9205 | } | 9161 | } |
| @@ -9210,39 +9166,6 @@ like any other error when calling a finalizer.) | |||
| 9210 | @itemize{ | 9166 | @itemize{ |
| 9211 | 9167 | ||
| 9212 | @item{ | 9168 | @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 | } | 9169 | } |
| 9247 | 9170 | ||
| 9248 | } | 9171 | } |
| @@ -9254,46 +9177,6 @@ to adjust its number of results to one. | |||
| 9254 | @itemize{ | 9177 | @itemize{ |
| 9255 | 9178 | ||
| 9256 | @item{ | 9179 | @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 | } | 9180 | } |
| 9298 | 9181 | ||
| 9299 | } | 9182 | } |
