diff options
Diffstat (limited to 'doc/lispref/symbols.texi')
| -rw-r--r-- | doc/lispref/symbols.texi | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/doc/lispref/symbols.texi b/doc/lispref/symbols.texi index a214a2d3fd8..5d71fb39a25 100644 --- a/doc/lispref/symbols.texi +++ b/doc/lispref/symbols.texi @@ -558,9 +558,12 @@ deleted from the local value of a hook variable when changing major modes. @xref{Setting Hooks}. @item pure +@cindex @code{pure} property If the value is non-@code{nil}, the named function is considered to be -side-effect free. Calls with constant arguments can be evaluated at -compile time. This may shift run time errors to compile time. +pure (@pxref{What Is a Function}). Calls with constant arguments can +be evaluated at compile time. This may shift run time errors to +compile time. Not to be confused with pure storage (@pxref{Pure +Storage}). @item risky-local-variable If the value is non-@code{nil}, the named variable is considered risky @@ -579,9 +582,13 @@ The value specifies a function for determining safe file-local values for the named variable. @xref{File Local Variables}. @item side-effect-free +@cindex @code{side-effect-free} property A non-@code{nil} value indicates that the named function is free of -side-effects, for determining function safety (@pxref{Function -Safety}) as well as for byte compiler optimizations. Do not set it. +side effects (@pxref{What Is a Function}), so the byte compiler may +ignore a call whose value is unused. If the property's value is +@code{error-free}, the byte compiler may even delete such unused +calls. In addition to byte compiler optimizations, this property is +also used for determining function safety (@pxref{Function Safety}). @item variable-documentation If non-@code{nil}, this specifies the named variable's documentation |