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純粋なbashのPS1から幅0のセクションを削除する

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純粋なbashのPS1から幅0のセクションを削除する

右に調整された文字列（つまり、端末の右側）を印刷する関数を作成しています。これには2つのことが必要です。

  1. 装飾された幅がゼロのすべての部分（色など）を含む文字列を印刷します。
  2. 幅0の部分（より正確には長さ）をすべて除いて文字列を印刷します。

明らかな理由で右にどれだけオフセットするかを知るには、[1]が必要で、[2]が必要です。terminal width-[2]

そのためにPS1/PS2と同じ形式を選択しました。\[との間に幅0のセクションを配置しました。\]

perl期待どおりに機能する貪欲ではない正規表現を使用して関数を作成しました。

# This needs zero-width parts surrounded by \[ and \] just like PS1/PS2
function _print_right_adjusted_perl() {
        local escaped_line printed_line nonzero_line forward

        #line with all zero-width parts escaped by \[ and \]
        escaped_line="${1}"

        # [1]: Only the \[ and \] markers removed; this will be the thing that is actually printed.
        printed_line="$(perl -pe 's|\\\[(.*?)\\\]|\1|g' <<<"${escaped_line}")"

        # [2]: all zero-with parts removed, including the markers \[ and \].
        nonzero_line="$(perl -pe 's|\\\[.*?\\\]||g' <<<"${escaped_line}")"


        # "carriage return" (literally) returns cursor to the first column of this row
        printf "$(tput cr)"

        # tput cuf N: move cursor forward N times
        forward="$(( "$(tput cols)" - "${#nonzero_line}" ))"
        printf "$(tput cuf "${forward}")"

        # print the actual text
        printf "${printed_line}"
}

_print_right_adjusted "\[$(tput setaf 7)\]my coloured thing"

その後、純粋なbashバージョンの作成を始めましたが、まだ問題がありました。

以下の機能が私の答えに置き換えられました。

# This needs zero-width parts surrounded by \[ and \] just like PS1/PS2
function _print_right_adjusted_old() {

        local printed_string="" has_length='true' first='true' added_part=''
        local -i printed_length=0 forward

        # split input string at backslashes. eg. turn:
        #    "normal \[zero-width\]colour string"
        # into:
        #    ( "normal" "[zero-width" "]colour string" )
        IFS='\'
        for part in ${1}; do
                # check what the first character is
                case "${part:0:1}" in
                        '[')
                             # start of a zero-width section
                             has_length='false';
                             # remove the marker
                             part="${part#'['}"
                             ;;
                        ']')
                             # end of a zero-width section
                             has_length='true';
                             # remove the marker
                             part="${part#']'}"
                             ;;
                        # not '\[' or '\]', re-add '\' except for the first segment
                        *) [[ "${first}" != 'true' ]] && part="\\${part}" ;;
                esac
                first='false'

                printed_string+="${part}"

                if [[ "${has_length}" == 'true' ]]; then
                        printed_length+="${#part}"
                fi
        done

        # cr: "carriage return" (literally) returns cursor to the first column of current row
        # cuf N: cursor-forward: move cursor N spaces forward (to the right)
        forward="$(( "$(tput cols)" - "${printed_length}" ))"
        printf "$(tput cr)$(tput cuf "${forward}")"

        # print the actual string
        printf "${printed_string}"
}

${variable@P}PS1などの変数を解釈するよりも、最後の行を置き換えることができ、そのprintf "${1@P}"行を削除できることを学びました。printed_string+="${part}"

ベストアンサー1

それ以来、私はこのスクリプトを2回書き直しました。

最初のバージョンはうまく機能しますが、1〜2文字ごとに繰り返されるlength/2ため、遅くなりますlength。

function _print_right_adjusted_2step() {
        local escaped_string="${1:?'need PS1-style string as 1st argument'}"

        local has_width='y'
        local -i length=0 terminal_width="$(tput cols)"

        # loop over string character by character and check 2 characters starting at ${i}
        for (( i=0; i<"${#escaped_string}"; i++ )); do case "${escaped_string:${i}:2}" in

                # when first character is a backslash, check for \[ or \] combination
                '\[') ((++i)); has_width='' ; ;;
                '\]') ((++i)); has_width='y'; ;;

                # when 2nd character is a backslash we go forward 1 character only so the backslash is first on the next loop iteration
                ?'\')          [[ -n "${has_width}" ]] && length+=1; ;;

                # when 2nd character is not a backslash we can skip ahead
                ?*)   ((++i)); [[ -n "${has_width}" ]] && length+=2; ;;
        esac; done

        local offset="$(( "${terminal_width}" - "${length}" ))"
        printf "$(tput cr)$(tput cuf "${offset}")${escaped_string@P}"
}

2番目のバージョンは数回だけ繰り返すので、はるかに高速です。 （個数\）+ 1

function _print_right_adjusted_new() {
        local escaped_string="${1:?'need PS1-style string as 1st argument'}"

        local prefix='' has_width='y' terminal_width="$(tput cols)" nonzero_string=''
        local -i length=0

        local IFS='\'
        for segment in ${escaped_string}; do
                #  with the 1st segment, prefix is ''  (empty string)
                # after the 1st segment, prefix is '\' (a backslash)
                case "${prefix}${segment:0:1}" in
                        # when first character is a backslash, check for \[ or \] combination
                        '\[') has_width='' ;              ;;
                        # remove the soon-to-be-added ']' from the length
                        '\]') has_width='y'; ((length--)) ;;
                        # add the missing '\' to the length
                        '\'?)                ((length++)) ;;
                esac

                if [[ -n "${has_width}" ]]; then
                    # use the line below if you need the actual content
                    # nonzero_string+="${segment}"
                    length+="${#segment}"
                fi
                prefix='\'
        done

        local offset="$(( "${terminal_width}" - "${length}" ))"
        printf "$(tput cr)$(tput cuf "${offset}")${escaped_string@P}"
}

その後、印刷オーバーヘッドなしで各バージョンを10,000回テストしましたが、すべてのバージョンが同じでした。

#!/bin/bash
set -euo pipefail

function _print_right_adjusted_2step() {
    local print_start_time="${EPOCHREALTIME/./}"

    local has_width='y' escaped_string="${1:?'need PS1-style string as 1st argument'}"

    local -i length=0 terminal_width=0 offset=0

    # loop over string character by character and include the next character in the check ( 2 characters starting at ${i} )
    for (( i=0; i<"${#escaped_string}"; i++ )); do case "${escaped_string:${i}:2}" in

        # when first character is a backslash, check for \[ or \] combination
        '\[') ((++i)); has_width='' ; ;;
        '\]') ((++i)); has_width='y'; ;;

        # when 2nd character is a backslash we go forward 1 character only so the backslash is first on the next loop iteration
        ?'\')          [[ -n "${has_width}" ]] && length+=1; ;;

        # when 2nd character is not a backslash we can skip ahead
        ?*)   ((++i)); [[ -n "${has_width}" ]] && length+=2; ;;
    esac; done

    #offset="$(( "${terminal_width}" - "${length}" ))"
    #printf "$(tput cr)$(tput cuf "${offset}")${escaped_string@P}"

    local print_end_time="${EPOCHREALTIME/./}"
    printf >&3 "$(( (print_end_time - print_start_time) ))"
    return 0
}

function _print_right_adjusted_new() {
    local print_start_time="${EPOCHREALTIME/./}"

    local escaped_string="${1:?'need PS1-style string as 1st argument'}"
    local prefix='' has_width='y'
    local -i length=0

    IFS='\'
    for segment in ${escaped_string}; do

        # loop over string character by character and include the next character in the check ( 2 characters starting at ${i} )
        case "${prefix}${segment:0:1}" in
            # when first character is a backslash, check for \[ or \] combination
            '\[') has_width='' ;              ;;
            # remove the soon-to-be-added ']' from the length
            '\]') has_width='y'; ((length--)) ;;
            # add the missing '\' to the length
            '\'?)                ((length++)) ;;
        esac

        [[ -n "${has_width}" ]] && length+="${#segment}"

        prefix='\'
    done

    #local offset="$(( "${terminal_width}" - "${length}" ))"
    #printf "$(tput cr)$(tput cuf "${offset}")${escaped_string@P}"

    local print_end_time="${EPOCHREALTIME/./}"
    printf >&3 "$(( (print_end_time - print_start_time) ))"
    return 0
}

function _print_right_adjusted_perl() {
    local print_start_time="${EPOCHREALTIME/./}"

    # line with all zero-width parts escaped by \[ and \]
    local escaped_string="${1:?'need PS1-style string as 1st argument'}"
    local nonzero_string offset terminal_width=0

    # line with all zero-with parts removed, including the markers \[ and \] 
    nonzero_string="$(perl -pe 's|\\\[.*?\\\]||g' <<<"${escaped_string}")"

    #terminal_width="$(tput cols)"
    #offset="$(( "${terminal_width}" - "${#nonzero_line}" ))"

    # tput cr: "carriage return", literally.
    # tput cuf N: move cursor forward N times
    #printf "$(tput cr)$(tput cuf "${offset}" )${escaped_string@P}"

    local print_end_time="${EPOCHREALTIME/./}"
    printf >&3 "$(( (print_end_time - print_start_time) ))"
    return 0
}


# https://stackoverflow.com/a/56151840
function sort_with_header() {
    sed -u '1q'; sort "${@}"
}


input="normal\[$(tput smul)\]underlined\[$(tput rmul)$(tput bold)$(tput setaf 5)\]color stuff\[$(tput sgr0)\]normal"

printf "starting test\n"
{
    printf >&3 "name\tms\n" 
    for f in $(seq 1 10000); do
        #printf '.'
        printf >&3 "2step\t"
        _print_right_adjusted_2step "${input}"
        printf >&3 "\nperl\t"
        _print_right_adjusted_perl "${input}"
        printf >&3 "\nnew\t"
        _print_right_adjusted_new "${input}"
        printf >&3 "\n"
    done
}  3> timing.txt
printf "\ntesting is done!\n"

<timing.txt datamash -H --sort --group name median 2 mode 2 mean 2 pstdev 2 | sort_with_header -h -k2 | column -t | tee stats.txt

任意の出力:

GroupBy(name)  median(ms)  mode(ms)  mean(ms)   pstdev(ms)
new            58          57        60.9599    8.6375165406499
2step          237         236       245.2142   31.085467961091
perl           1003        997       1011.1479  41.703832265033

私は新しいバージョンを成功と呼びます:-)

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