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Diffstat (limited to 'Doc/Zsh/func.yo')
| -rw-r--r-- | Doc/Zsh/func.yo | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/Doc/Zsh/func.yo b/Doc/Zsh/func.yo index 7edad7f23..7b71e34e9 100644 --- a/Doc/Zsh/func.yo +++ b/Doc/Zsh/func.yo @@ -13,6 +13,43 @@ Functions are executed like commands with the arguments passed as positional parameters. (See noderef(Command Execution).) +Parameters declared by any of the `tt(typeset)' family of commands +during the execution of a function become em(local) to the function +unless the `tt(-g)' option is used. This is the em(scope) of the +parameter, which extends dynamically to any other functions called by +the declaring function. In most cases, local parameters take the +place of any other parameter having the same name that was assigned or +declared in an earlier function scope. +(See noderef(Local Parameters).) + +A named parameter declared with the `tt(-n)' option to any of the +`tt(typeset)' commands becomes a reference to a parameter in scope at +the time of assignment to the named reference, which may be at a +different call level than the declaring function. For this reason, +it is good practice to declare a named reference as soon as the +referent parameter is in scope, and as early as possible in the +function if the reference is to a parameter in a calling scope. + +A typical use of named references is to pass the name +of the referent as a positional parameter. In this case it is +good practice to use the tt(-u) option to reference the calling +scope. For example, +ifzman() +example(pop+LPAR()RPAR() { + local -nu ref=$1 + local last=$ref[$#ref] + ref[$#ref]=LPAR()RPAR() + print -r -- $last +} +array=LPAR() a list of five values RPAR() +pop array) + +prints the word `tt(values)' and shortens `tt($array)' to +`tt(LPAR() a list of five RPAR())'. With tt(-nu), `tt(ref)' becomes a +reference to `tt(array)' in the caller. There are no local parameters in +tt(pop) at the time `tt(ref=$1)' is assigned, so in this example tt(-u) +could have been omitted, but it makes the intention clear. + Functions execute in the same process as the caller and share all files and present working directory with the @@ -276,7 +313,7 @@ the history file. In case of a conflict, the first non-zero status value is taken. A hook function may call `tt(fc -p) var(...)' to switch the history -context so that the history is saved in a different file from the +context so that the history is saved in a different file from that in the global tt(HISTFILE) parameter. This is handled specially: the history context is automatically restored after the processing of the history line is finished. |