notes eiro.github.io ajoutées pour fusion

eiro.md

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+% Notes zsh
+
+# scalars
+
+are nothing but strings
+
+    echo 3 + 3
+
+are nothing but strings
+
+## Datastructures
+
+### Associations
+
+### from line records to associations
+
+how to read this line in an association? 
+
+     mc:x:1002:100:Marc Chantreux,,,:/home/mc:/bin/zsh
+
+the perl version would be
+
+    my %user;
+    @user{qw( login x uid gid gecos home shell )} = split /:/, $line
+
+easier to maintain if you store the keys in a separate list
+
+    my @attrs = qw( login x uid gid gecos home shell );
+    my %user;
+    @user{@attrs} = split /:/, $line
+
+the zsh version isn't longuer
+
+    my% user
+    entry="$( getent passwd mc )"
+    attrs=( login x uid gid gecos home shell )
+    IFS=: read user\[$^attrs] <<< $entry
+
+got it? no? so hack it. the expanded version is
+
+    my% user
+    entry="$( getent passwd mc )"
+
+    IFS=: read  \
+    user[login] \
+    user[x]     \
+    user[uid]   \
+    user[gid]   \
+    user[gecos] \
+    user[home]  \
+    user[shell] <<< $entry
+
+but we can use brace expansions here
+
+    # /!\ this doesn't work because zsh recognize a glob 
+    #     and wants to expand it
+
+    user[{login,x,uid,gid,gecos,home,shell}] <<< $entry
+
+you're one caracter left
+
+    user\[{login,x,uid,gid,gecos,home,shell}] <<< $entry
+
+now you need to put the keys in an array
+
+    attrs=( login x login x uid gid gecos home shell )
+    user\[$^attrs] <<< $entry
+
+### serialize an association
+
+see http://www.zsh.org/mla/users/2012/msg00005.html. note that it also work
+with P. so we can imagine a `pp` (ruby "pretty print") as
+
+    pp () {
+        case ${(Pt)1} {
+            (array)       print "$1=(${(Pq-)1})"
+            (association) print "my% $1=(${(P@kvq-)1})" ;;
+            (*)           ... ;;
+        }
+    }
+
+### serialize a list of variables
+
+    attrs=( login x uid gid gecos home shell )
+    getent passwd mc | IFS=: read $attrs
+    eval "print \$${(j,:$,)attrs}"
+
+### awk alike functions
+
+    getent passwd | read -A argv
+    print $1 # gets the login
+
+# zsh aliases i'm happy about
+
+years ago, i was very skeptical when i saw this
+
+    alias g="git"
+
+in the
+[Franck Cuny's .bashrc](https://github.com/franckcuny/home/blob/master/bashrc).
+I argued it wasn't worth to alias a command with such a short name.
+Franck just replied "it's faster" and this chat was as short as a
+smalltalk.
+
+Months later, i thought to myself it was worth to add 1 line in my `.zshenv`
+to give it a try. and it was worth! so f`******` worth!
+
+Since then, i have a simple rule: if
+
+* the average number of use is more than 3times/h (every day)
+* the shorthand shorter or equals 1/3 the long of the original
+
+it deserve a shorthand! so mine are
+
+    alias v=vim
+    alias z=zsh
+    alias s=ssh
+    alias l='print -l'
+    sz () { ssh "$@" zsh } 
+    alias g=git
+    alias @='for it'
+    alias @-='while {read it}'
+    alias %='for k v'
+
+`~/.ssh/config` also have some shorthands, for example 
+
+    host gh
+    hostname github.com
+    user git
+
+    host w
+    hostname www.mycompagny.example.com
+    user www-data
+
+    host db
+    hostname www.mycompagny.example.com
+    user operator
+
+so now i can write things like
+
+    l "select * from table" | s db | v -
+
+so i launch an sql query using the default database configured in 
+`db@hostname www.mycompagny.example.com/.my.cnf` and get the result
+in a vim buffer, ready to be edited.
+
+if you're comming from langages like `perl`, `livescript`, `groovy` or
+any of those langages coming with partial applications or context variables,
+you miss `it` (`$_` in `perl`). don't you? so just use it.
+
+both
+
+    seq 10|@- { l "$it * 3 = $[it*3]" }
+    @ ( {1..10} ) l "$it * 3 = $[it*3]"
+
+will produce
+
+    1 * 3 = 3
+    2 * 3 = 6
+    3 * 3 = 9
+    4 * 3 = 12
+    5 * 3 = 15
+    6 * 3 = 18
+    7 * 3 = 21
+    8 * 3 = 24
+    9 * 3 = 27
+    10 * 3 = 30
+
+thanks to variable interpolations, the equivalent of `it` in livescript (or `_
+prototype` in perl) can be written as `${1:=$it}`.
+
+    remote-date () { s ${1:=$it} date }
+    @ ($servers) remote-date
+
+i also have more `perl inspired` features including ̀ warn`, `die` and the
+yada-yada operator (`...`):
+
+    warn () {
+            LAST_ERROR=$? 
+            print -u2 "$*"
+            return $LAST_ERROR
+    }
+    die () {
+            LAST_ERROR=$? 
+            print -u2 "$*"
+            exit $LAST_ERROR
+    }
+    alias error=warn "in $0 line $LINENO:"
+    alias ...='{error Unimplemented; return 255}'
+
+a more complete example is
+
+    # server_exists () { grep -q ${1-${it?name of the server} ~/.servers }
+    # @ ( srv-{web,db,mq} ) { server_exists ||error "$it doesn't exist"}
+
+    in zsh line 2: srv-web doesn't exist
+    in zsh line 2: srv-db doesn't exist
+
+    # server_exists || ...
+
+        in zsh line 1: Unimplemented
+
+some of those ideas could be shared using
+using [uze](http://zsh-uze.github.io/)).
+
+# piping from vim
+
+from vim, visually select your sql query and type
+
+    '<,'>!s db-server mysql
+
+since each results are data to write the next query or command, i spend much of
+my time in vim now.
+
+
+
+
+
+