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@glebm @walgitrus @thomas-mcdonald @sbandyopadhyay @lazyatom
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require_relative 'char_string_scanner'
require 'bootstrap-sass/version'
# This is the script used to automatically convert all of twbs/bootstrap LESS to Sass.
#
# Most differences are fixed by regexps and other forms of string substitution.
# There are Bootstrap-specific workarounds for the lack of parent selectors, recursion, mixin namespaces, extend within @media, etc in Sass 3.2.
class Converter
module LessConversion
# Some regexps for matching bits of SCSS:
SELECTOR_CHAR = '\[\]$\w\-{}#,.:&>@'
# 1 selector (the part before the {)
SELECTOR_RE = /[#{SELECTOR_CHAR}]+[#{SELECTOR_CHAR}\s]*/
# 1 // comment
COMMENT_RE = %r((?:^[ \t]*//[^\n]*\n))
# 1 {, except when part of @{ and #{
RULE_OPEN_BRACE_RE = /(?<![@#\$])\{/
# same as the one above, but in reverse (on a reversed string)
RULE_OPEN_BRACE_RE_REVERSE = /\{(?![@#\$])/
# match closed brace, except when \w precedes }, or when }[.'"]. a heurestic to exclude } that are not selector body close }
RULE_CLOSE_BRACE_RE = /(?<!\w)\}(?![.'"])/
RULE_CLOSE_BRACE_RE_REVERSE = /(?<![.'"])\}(?!\w)/
# match any brace that opens or closes a properties body
BRACE_RE = /#{RULE_OPEN_BRACE_RE}|#{RULE_CLOSE_BRACE_RE}/m
BRACE_RE_REVERSE = /#{RULE_OPEN_BRACE_RE_REVERSE}|#{RULE_CLOSE_BRACE_RE_REVERSE}/m
# valid characters in mixin definitions
SCSS_MIXIN_DEF_ARGS_RE = /[\w\-,\s$:#%()]*/
LESS_MIXIN_DEF_ARGS_RE = /[\w\-,;.\s@:#%()]*/
# These mixins will get vararg definitions in SCSS (not supported by LESS):
NESTED_MIXINS = {'#gradient' => 'gradient'}
# These mixins will get vararg definitions in SCSS (not supported by LESS):
VARARG_MIXINS = %w(
scale transition transition-duration transition-property transition-transform box-shadow
)
# A list of classes that will be extracted into mixins
# Only the top-level selectors of form .CLASS { ... } are extracted. CLASS must not be used in any other rule definition.
# This is a work-around for libsass @extend issues
CLASSES_TO_MIXINS = %w(
list-unstyled form-inline
)
# Convert a snippet of bootstrap LESS to Scss
def convert_less(less)
less = convert_to_scss(less)
less = yield(less) if block_given?
less
end
def shared_mixins
@shared_mixins ||= begin
log_status ' Reading shared mixins from mixins.less'
CLASSES_TO_MIXINS + read_mixins(read_files('less', bootstrap_less_files.grep(/mixins\//)).values.join("\n"),
nested: NESTED_MIXINS)
end
end
def process_stylesheet_assets
log_status 'Processing stylesheets...'
files = read_files('less', bootstrap_less_files)
save_to = @save_to[:scss]
log_status ' Converting LESS files to Scss:'
files.each do |name, file|
log_processing name
# apply common conversions
file = convert_less(file)
file = replace_all file, %r{// stylelint-disable.*?\n+}, '', optional: true
if name.start_with?('mixins/')
file = varargify_mixin_definitions(file, *VARARG_MIXINS)
%w(responsive-(in)?visibility input-size text-emphasis-variant bg-variant).each do |mixin|
file = parameterize_mixin_parent_selector file, mixin if file =~ /#{mixin}/
end
NESTED_MIXINS.each do |sel, name|
file = flatten_mixins(file, sel, name) if /#{Regexp.escape(sel)}/ =~ file
end
file = replace_all file, /(?<=[.-])\$state/, '#{$state}' if file =~ /[.-]\$state/
end
case name
when 'mixins/buttons.less'
file = replace_all file, /(\.dropdown-toggle)&/, '&\1'
when 'mixins/list-group.less'
file = replace_rules(file, ' .list-group-item-') { |rule| extract_nested_rule rule, 'a&' }
when 'mixins/gradients.less'
file = replace_ms_filters(file)
file = deinterpolate_vararg_mixins(file)
when 'mixins/vendor-prefixes.less'
# remove second scale mixins as this is handled via vararg in the first one
file = replace_rules(file, Regexp.escape('@mixin scale($ratioX, $ratioY...)')) { '' }
when 'mixins/grid-framework.less'
file = convert_grid_mixins file
when 'component-animations.less'
file = extract_nested_rule file, "#{SELECTOR_RE}&\\.in"
when 'responsive-utilities.less'
file = apply_mixin_parent_selector file, '\.(?:visible|hidden)'
when 'variables.less'
file = insert_default_vars(file)
file = ['$bootstrap-sass-asset-helper: false !default;', file].join("\n")
file = replace_all file, %r{(\$icon-font-path): \s*"(.*)" (!default);}, "\n" + unindent(<<-SCSS, 14)
// [converter] If $bootstrap-sass-asset-helper if used, provide path relative to the assets load path.
// [converter] This is because some asset helpers, such as Sprockets, do not work with file-relative paths.
\\1: if($bootstrap-sass-asset-helper, "bootstrap/", "\\2bootstrap/") \\3;
SCSS
when 'breadcrumbs.less'
file = replace_all file, /(.*)(\\00a0)/, unindent(<<-SCSS, 8) + "\\1\#{$nbsp}"
// [converter] Workaround for https://github.com/sass/libsass/issues/1115
$nbsp: "\\2";
SCSS
when 'close.less'
# extract .close { button& {...} } rule
file = extract_nested_rule file, 'button&'
when 'dropdowns.less'
file = replace_all file, /@extend \.dropdown-menu-right;/, 'right: 0; left: auto;'
file = replace_all file, /@extend \.dropdown-menu-left;/, 'left: 0; right: auto;'
when 'forms.less'
file = extract_nested_rule file, 'textarea&'
file = apply_mixin_parent_selector(file, '\.input-(?:sm|lg)')
file = replace_rules file, /\.form-group-(?:sm|lg)/ do |rule|
apply_mixin_parent_selector rule, '.form-control'
end
when 'navbar.less'
file = replace_all file, /(\s*)\.navbar-(right|left)\s*\{\s*@extend\s*\.pull-(right|left);\s*/, "\\1.navbar-\\2 {\\1 float: \\2 !important;\\1"
when 'tables.less'
file = replace_all file, /(@include\s*table-row-variant\()(\w+)/, "\\1'\\2'"
when 'thumbnails.less', 'labels.less', 'badges.less', 'buttons.less'
file = extract_nested_rule file, 'a&'
when 'glyphicons.less'
file = replace_rules(file, /\s*@font-face/) { |rule| replace_asset_url rule, :font }
when 'type.less'
file = apply_mixin_parent_selector(file, '\.(text|bg)-(success|primary|info|warning|danger)')
# .bg-primary will not get patched automatically as it includes an additional rule. fudge for now
file = replace_all(file, " @include bg-variant($brand-primary);\n}", "}\n@include bg-variant('.bg-primary', $brand-primary);")
end
path = File.join save_to, name.sub(/\.less$/, '.scss')
path = File.join File.dirname(path), '_' + File.basename(path)
save_file(path, file)
log_processed File.basename(path)
end
# move bootstrap/_bootstrap.scss to _bootstrap.scss adjusting import paths
main_from = "#{save_to}/_bootstrap.scss"
main_to = File.expand_path("#{save_to}/../_bootstrap.scss")
save_file main_to, File.read(main_from).gsub(/ "/, ' "bootstrap/')
File.delete(main_from)
# generate variables template
save_file 'templates/project/_bootstrap-variables.sass',
"// Override Bootstrap variables here (defaults from bootstrap-sass v#{Bootstrap::VERSION}):\n\n" +
File.read("#{save_to}/_variables.scss").lines[1..-1].join.gsub(/^(?=\$)/, '// ').gsub(/ !default;/, '')
end
def bootstrap_less_files
@bootstrap_less_files ||= get_paths_by_type('less', /\.less$/)
end
# apply general less to scss conversion
def convert_to_scss(file)
# get local mixin names before converting the definitions
mixins = shared_mixins + read_mixins(file)
file = replace_vars(file)
file = replace_mixin_definitions(file)
file = replace_mixins(file, mixins)
file = extract_mixins_from_selectors(file, CLASSES_TO_MIXINS.inject({}) { |h, cl| h.update(".#{cl}" => cl) })
file = replace_spin(file)
file = replace_fadein(file)
file = replace_image_urls(file)
file = replace_escaping(file)
file = convert_less_ampersand(file)
file = deinterpolate_vararg_mixins(file)
file = replace_calculation_semantics(file)
file = replace_file_imports(file)
file = wrap_at_groups_with_at_root(file)
file
end
def wrap_at_groups_with_at_root(file)
replace_rules(file, /@(?:font-face|-ms-viewport)/) { |rule, _pos|
%Q(@at-root {\n#{indent rule, 2}\n})
}
end
def sass_fn_exists(fn)
%Q{(#{fn}("") != unquote('#{fn}("")'))}
end
def replace_asset_url(rule, type)
replace_all rule, /url\((.*?)\)/, "url(if($bootstrap-sass-asset-helper, twbs-#{type}-path(\\1), \\1))"
end
# convert recursively evaluated selector $list to @for loop
def mixin_all_grid_columns(css, selector: raise('pass class'), from: 1, to: raise('pass to'))
mxn_def = css.each_line.first.strip
# inject local variables as default arguments
# this is to avoid overwriting outer variables with the same name with Sass <= 3.3
# see also: https://github.com/twbs/bootstrap-sass/issues/636
locals = <<-SASS.strip
$i: #{from}, $list: "#{selector}"
SASS
mxn_def.sub!(/(\(?)(\)\s*\{)/) { "#{$1}#{', ' if $1.empty?}#{locals}#{$2}" }
step_body = (css =~ /\$list \{\n(.*?)\n[ ]*\}/m) && $1
<<-SASS
// [converter] This is defined recursively in LESS, but Sass supports real loops
#{mxn_def}
@for $i from (#{from} + 1) through #{to} {
$list: "\#{$list}, #{selector}";
}
\#{$list} {
#{unindent step_body, 2}
}
}
SASS
end
# convert grid mixins LESS when => Sass @if
def convert_grid_mixins(file)
file = replace_rules file, /@mixin make-grid-columns/, comments: false do |css, pos|
mixin_all_grid_columns css, selector: '.col-xs-#{$i}, .col-sm-#{$i}, .col-md-#{$i}, .col-lg-#{$i}', to: '$grid-columns'
end
file = replace_rules file, /@mixin float-grid-columns/, comments: false do |css, pos|
mixin_all_grid_columns css, selector: '.col-#{$class}-#{$i}', to: '$grid-columns'
end
file = replace_rules file, /@mixin calc-grid-column/ do |css|
css = indent css.gsub(/.*when (.*?) {/, '@if \1 {').gsub(/(\$[\w-]+)\s+=\s+(\w+)/, '\1 == \2').gsub(/(?<=-)(\$[a-z]+)/, '#{\1}')
if css =~ /== width/
css = "@mixin calc-grid-column($index, $class, $type) {\n#{css}"
elsif css =~ /== offset/
css += "\n}"
end
css
end
file = replace_rules file, /@mixin loop-grid-columns/ do |css|
unindent <<-SASS, 8
// [converter] This is defined recursively in LESS, but Sass supports real loops
@mixin loop-grid-columns($columns, $class, $type) {
@for $i from 0 through $columns {
@include calc-grid-column($i, $class, $type);
}
}
SASS
end
file
end
# We need to keep a list of shared mixin names in order to convert the includes correctly
# Before doing any processing we read shared mixins from a file
# If a mixin is nested, it gets prefixed in the list (e.g. #gradient > .horizontal to 'gradient-horizontal')
def read_mixins(mixins_file, nested: {})
mixins = get_mixin_names(mixins_file, silent: true)
nested.each do |selector, prefix|
# we use replace_rules without replacing anything just to use the parsing algorithm
replace_rules(mixins_file, selector) { |rule|
mixins += get_mixin_names(unindent(unwrap_rule_block(rule)), silent: true).map { |name| "#{prefix}-#{name}" }
rule
}
end
mixins.uniq!
mixins.sort!
log_file_info "mixins: #{mixins * ', '}" unless mixins.empty?
mixins
end
def get_mixin_names(file, opts = {})
names = get_css_selectors(file).join("\n" * 2).scan(/^\.([\w-]+)\(#{LESS_MIXIN_DEF_ARGS_RE}\)(?: when.*?)?[ ]*\{/).map(&:first).uniq.sort
log_file_info "mixin defs: #{names * ', '}" unless opts[:silent] || names.empty?
names
end
# margin: a -b
# LESS: sets 2 values
# Sass: sets 1 value (a-b)
# This wraps a and -b so they evaluates to 2 values in Sass
def replace_calculation_semantics(file)
# split_prop_val.call('(@navbar-padding-vertical / 2) -@navbar-padding-horizontal')
# #=> ["(navbar-padding-vertical / 2)", "-navbar-padding-horizontal"]
split_prop_val = proc { |val|
s = CharStringScanner.new(val)
r = []
buff = ''
d = 0
prop_char = %r([\$\w\-/\*\+%!])
while (token = s.scan_next(/([\)\(]|\s+|#{prop_char}+)/))
buff << token
case token
when '('
d += 1
when ')'
d -= 1
if d == 0
r << buff
buff = ''
end
when /\s/
if d == 0 && !buff.strip.empty?
r << buff
buff = ''
end
end
end
r << buff unless buff.empty?
r.map(&:strip)
}
replace_rules file do |rule|
replace_properties rule do |props|
props.gsub /(?<!\w)([\w-]+):(.*?);/ do |m|
prop, vals = $1, split_prop_val.call($2)
next m unless vals.length >= 2 && vals.any? { |v| v =~ /^[\+\-]\$/ }
transformed = vals.map { |v| v.strip =~ %r(^\(.*\)$) ? v : "(#{v})" }
log_transform "property #{prop}: #{transformed * ' '}", from: 'wrap_calculation'
"#{prop}: #{transformed * ' '};"
end
end
end
end
# @import "file.less" to "#{target_path}file;"
def replace_file_imports(less, target_path = '')
less.gsub %r([@\$]import ["|']([\w\-/]+).less["|'];),
%Q(@import "#{target_path}\\1";)
end
def replace_all(file, regex, replacement = nil, optional: false, &block)
log_transform regex, replacement
new_file = file.gsub(regex, replacement, &block)
raise "replace_all #{regex}, #{replacement} NO MATCH" if !optional && file == new_file
new_file
end
# @mixin a() { tr& { color:white } }
# to:
# @mixin a($parent) { tr#{$parent} { color: white } }
def parameterize_mixin_parent_selector(file, rule_sel)
log_transform rule_sel
param = '$parent'
replace_rules(file, '^\s*@mixin\s*' + rule_sel) do |mxn_css|
mxn_css.sub! /(?=@mixin)/, "// [converter] $parent hack\n"
# insert param into mixin def
mxn_css.sub!(/(@mixin [\w-]+)\(([\$\w\-,\s]*)\)/) { "#{$1}(#{param}#{', ' if $2 && !$2.empty?}#{$2})" }
# wrap properties in #{$parent} { ... }
replace_properties(mxn_css) { |props|
next props if props.strip.empty?
spacer = ' ' * indent_width(props)
"#{spacer}\#{#{param}} {\n#{indent(props.sub(/\s+\z/, ''), 2)}\n#{spacer}}"
}
# change nested& rules to nested#{$parent}
replace_rules(mxn_css, /.*&[ ,:]/) { |rule| replace_in_selector rule, /&/, "\#{#{param}}" }
end
end
# extracts rule immediately after it's parent, and adjust the selector
# .x { textarea& { ... }}
# to:
# .x { ... }
# textarea.x { ... }
def extract_nested_rule(file, selector, new_selector = nil)
matches = []
# first find the rules, and remove them
file = replace_rules(file, "\s*#{selector}", comments: true) { |rule, pos, css|
new_sel = new_selector || "#{get_selector(rule).gsub(/&/, selector_for_pos(css, pos.begin))}"
matches << [rule, pos, new_sel]
indent "// [converter] extracted #{get_selector(rule)} to #{new_sel}".tr("\n", ' ').squeeze(' '), indent_width(rule)
}
raise "extract_nested_rule: no such selector: #{selector}" if matches.empty?
# replace rule selector with new_selector
matches.each do |m|
m[0].sub! /(#{COMMENT_RE}*)^(\s*).*?(\s*){/m, "\\1\\2#{m[2]}\\3{"
log_transform selector, m[2]
end
replace_substrings_at file,
matches.map { |_, pos| close_brace_pos(file, pos.begin, 1) + 1 },
matches.map { |rule, _| "\n\n" + unindent(rule) }
end
# .visible-sm { @include responsive-visibility() }
# to:
# @include responsive-visibility('.visible-sm')
def apply_mixin_parent_selector(file, rule_sel)
log_transform rule_sel
replace_rules file, '\s*' + rule_sel, comments: false do |rule, rule_pos, css|
body = unwrap_rule_block(rule.dup).strip
next rule unless body =~ /^@include \w+/m || body =~ /^@media/ && body =~ /\{\s*@include/
rule =~ /(#{COMMENT_RE}*)([#{SELECTOR_CHAR}\s*]+?)#{RULE_OPEN_BRACE_RE}/
cmt, sel = $1, $2.strip
# take one up selector chain if this is an &. selector
if sel.start_with?('&')
parent_sel = selector_for_pos(css, rule_pos.begin)
sel = parent_sel + sel[1..-1]
end
# unwrap, and replace @include
unindent unwrap_rule_block(rule).gsub(/(@include [\w-]+)\(?([\$\w\-,\s]*)\)?/) {
name, args = $1, $2
sel.gsub(/\s+/, ' ').split(/,\s*/ ).map { |sel_part|
"#{cmt}#{name}('#{sel_part}'#{', ' if args && !args.empty?}#{args})"
}.join(";\n")
}
end
end
# #gradient > { @mixin horizontal ... }
# to:
# @mixin gradient-horizontal
def flatten_mixins(file, container, prefix)
log_transform container, prefix
replace_rules file, Regexp.escape(container) do |mixins_css|
unindent unwrap_rule_block(mixins_css).gsub(/@mixin\s*([\w-]+)/, "@mixin #{prefix}-\\1")
end
end
# .btn { ... } -> @mixin btn { ... }; .btn { @include btn }
def extract_mixins_from_selectors(file, selectors_to_mixins)
selectors_to_mixins.each do |selector, mixin|
file = replace_rules file, Regexp.escape(selector), prefix: false do |selector_css|
log_transform "#{selector} { ... } -> @mixin #{mixin} { ... }; #{selector} { @include #{mixin} } ", from: 'extract_mixins_from_selectors'
<<-SCSS
// [converter] extracted from `#{selector}` for libsass compatibility
@mixin #{mixin} {#{unwrap_rule_block(selector_css)}
}
// [converter] extracted as `@mixin #{mixin}` for libsass compatibility
#{selector} {
@include #{mixin};
}
SCSS
end
end
file
end
# @include and @extend from LESS:
# .mixin() -> @include mixin()
# #scope > .mixin() -> @include scope-mixin()
# &:extend(.mixin all) -> @include mixin()
def replace_mixins(less, mixin_names)
mixin_pattern = /(?<=^|\s)((?:[#|\.][\w-]+\s*>\s*)*)\.([\w-]+)\((.*)\)(?!\s\{)/
less = less.gsub(mixin_pattern) do |_|
scope, name, args = $1, $2, $3
scope = scope.scan(/[\w-]+/).join('-') + '-' unless scope.empty?
args = "(#{args.tr(';', ',')})" unless args.empty?
if name && mixin_names.include?("#{scope}#{name}")
"@include #{scope}#{name}#{args}"
else
"@extend .#{scope}#{name}"
end
end
less.gsub /&:extend\((#{SELECTOR_RE})(?: all)?\)/ do
selector = $1
selector =~ /\.([\w-]+)/
mixin = $1
if mixin && mixin_names.include?(mixin)
"@include #{mixin}"
else
"@extend #{selector}"
end
end
end
# change Microsoft filters to Sass calling convention
def replace_ms_filters(file)
log_transform
file.gsub(
/filter: e\(%\("progid:DXImageTransform.Microsoft.gradient\(startColorstr='%d', endColorstr='%d', GradientType=(\d)\)", ?argb\(([\-$\w]+)\), ?argb\(([\-$\w]+)\)\)\);/,
%Q(filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='\#{ie-hex-str(\\2)}', endColorstr='\#{ie-hex-str(\\3)}', GradientType=\\1);)
)
end
# unwraps topmost rule block
# #sel { a: b; }
# to:
# a: b;
def unwrap_rule_block(css)
css[(css =~ RULE_OPEN_BRACE_RE) + 1..-1].sub(/\n?}\s*\z/m, '')
end
def replace_mixin_definitions(less)
less.gsub(/^(\s*)\.([\w-]+\(.*\))(\s*\{)/) { |match|
"#{$1}@mixin #{$2.tr(';', ',')}#{$3}".sub(/,\)/, ')')
}
end
def replace_vars(less)
less = less.dup
# skip header comment
less =~ %r(\A/\*(.*?)\*/)m
from = $~ ? $~.to_s.length : 0
less[from..-1] = less[from..-1].
gsub(/(?!@mixin|@media|@page|@keyframes|@font-face|@-\w)@/, '$').
# variables that would be ignored by gsub above: e.g. @page-header-border-color
gsub(/@(page[\w-]+)/, '$\1')
less
end
def replace_spin(less)
less.gsub(/(?![\-$@.])spin(?!-)/, 'adjust-hue')
end
def replace_fadein(less)
less.gsub(/(?![\-$@.])fadein\((.*?),\s*(.*?)%\)/) { "fade_in(#{$1}, #{$2.to_i / 100.0})" }
end
def replace_image_urls(less)
less.gsub(/background-image: url\("?(.*?)"?\);/) { |s| replace_asset_url s, :image }
end
def replace_escaping(less)
less = less.gsub(/~"([^"]+)"/, '\1').gsub(/~'([^']+)'/, '\1') # Get rid of ~"" escape
less.gsub!(/\$\{([^}]+)\}/, '$\1') # Get rid of @{} escape
# interpolate variables in strings, e.g. url("$file-1x") => url("#{$file-1x}")
less.gsub!(/"[^"\n]*"/) { |str| str.gsub(/\$[^"\n$.\\]+/, '#{\0}') }
less.gsub(/(\W)e\(%\("?([^"]*)"?\)\)/, '\1\2') # Get rid of e(%("")) escape
end
def insert_default_vars(scss)
log_transform
scss.gsub(/^(\$.+);/, '\1 !default;')
end
# Converts &-
def convert_less_ampersand(less)
regx = /^\.badge\s*\{[\s\/\w\(\)]+(&{1}-{1})\w.*?^}$/m
tmp = ''
less.scan(/^(\s*&)(-[\w\[\]]+\s*\{.+})$/) do |ampersand, css|
tmp << ".badge#{css}\n"
end
less.gsub(regx, tmp)
end
# unindent by n spaces
def unindent(txt, n = 2)
txt.gsub /^[ ]{#{n}}/, ''
end
# indent by n spaces
def indent(txt, n = 2)
spaces = ' ' * n
txt.gsub /^/, spaces
end
# get indent length from the first line of txt
def indent_width(txt)
txt.match(/\A\s*/).to_s.length
end
# @mixin transition($transition) {
# to:
# @mixin transition($transition...) {
def varargify_mixin_definitions(scss, *mixins)
scss = scss.dup
replaced = []
mixins.each do |mixin|
if scss.gsub! /(@mixin\s*#{Regexp.quote(mixin)})\((#{SCSS_MIXIN_DEF_ARGS_RE})\)/, '\1(\2...)'
replaced << mixin
end
end
log_transform *replaced unless replaced.empty?
scss
end
# @include transition(#{border-color ease-in-out .15s, box-shadow ease-in-out .15s})
# to
# @include transition(border-color ease-in-out .15s, box-shadow ease-in-out .15s)
def deinterpolate_vararg_mixins(scss)
scss = scss.dup
VARARG_MIXINS.each do |mixin|
if scss.gsub! /(@include\s*#{Regexp.quote(mixin)})\(\s*\#\{([^}]+)\}\s*\)/, '\1(\2)'
log_transform mixin
end
end
scss
end
# get full selector for rule_block
def get_selector(rule_block)
sel = /^\s*(#{SELECTOR_RE}?)\s*\{/.match(rule_block) && $1 && $1.strip
sel.sub /\s*\{\n\s.*/m, ''
end
# replace CSS rule blocks matching rule_prefix with yield(rule_block, rule_pos)
# will also include immediately preceding comments in rule_block
#
# option :comments -- include immediately preceding comments in rule_block
#
# replace_rules(".a{ \n .b{} }", '.b') { |rule, pos| ">#{rule}<" } #=> ".a{ \n >.b{}< }"
def replace_rules(less, selector = SELECTOR_RE, options = {}, &block)
options = {prefix: true, comments: true}.merge(options || {})
less = less.dup
s = CharStringScanner.new(less)
rule_re = if options[:prefix]
/(?:#{selector}[#{SELECTOR_CHAR})=(\s]*?#{RULE_OPEN_BRACE_RE})/
else
/#{selector}[\s]*#{RULE_OPEN_BRACE_RE}/
end
rule_start_re = if options[:comments]
/(?:#{COMMENT_RE}*)^#{rule_re}/
else
/^#{rule_re}/
end
positions = []
while (rule_start = s.scan_next(rule_start_re))
pos = s.pos
positions << (pos - rule_start.length..close_brace_pos(less, pos - 1))
end
replace_substrings_at(less, positions, &block)
less
end
# Get a all top-level selectors (with {)
def get_css_selectors(css, opts = {})
s = CharStringScanner.new(css)
selectors = []
while s.scan_next(RULE_OPEN_BRACE_RE)
brace_pos = s.pos
def_pos = css_def_pos(css, brace_pos+1, -1)
sel = css[def_pos.begin..brace_pos - 1].dup
sel.strip! if opts[:strip]
selectors << sel
sel.dup.strip
s.pos = close_brace_pos(css, brace_pos, 1) + 1
end
selectors
end
# replace in the top-level selector
# replace_in_selector('a {a: {a: a} } a {}', /a/, 'b') => 'b {a: {a: a} } b {}'
def replace_in_selector(css, pattern, sub)
# scan for selector positions in css
s = CharStringScanner.new(css)
prev_pos = 0
sel_pos = []
while (brace = s.scan_next(RULE_OPEN_BRACE_RE))
pos = s.pos
sel_pos << (prev_pos .. pos - 1)
s.pos = close_brace_pos(css, s.pos - 1) + 1
prev_pos = pos
end
replace_substrings_at(css, sel_pos) { |s| s.gsub(pattern, sub) }
end
# replace first level properties in the css with yields
# replace_properties("a { color: white }") { |props| props.gsub 'white', 'red' }
def replace_properties(css, &block)
s = CharStringScanner.new(css)
s.skip_until /#{RULE_OPEN_BRACE_RE}\n?/
from = s.pos
m = s.scan_next(/\s*#{SELECTOR_RE}#{RULE_OPEN_BRACE_RE}/) || s.scan_next(/\s*#{RULE_CLOSE_BRACE_RE}/)
to = s.pos - m.length - 1
replace_substrings_at css, [(from .. to)], &block
end
# immediate selector of css at pos
def selector_for_pos(css, pos, depth = -1)
css[css_def_pos(css, pos, depth)].dup.strip
end
# get the pos of css def at pos (search backwards)
def css_def_pos(css, pos, depth = -1)
to = open_brace_pos(css, pos, depth)
prev_def = to - (css[0..to].reverse.index(RULE_CLOSE_BRACE_RE_REVERSE) || to) + 1
from = prev_def + 1 + (css[prev_def + 1..-1] =~ %r(^\s*[^\s/]))
(from..to - 1)
end
# next matching brace for brace at from
def close_brace_pos(css, from, depth = 0)
s = CharStringScanner.new(css[from..-1])
while (b = s.scan_next(BRACE_RE))
depth += (b == '}' ? -1 : +1)
break if depth.zero?
end
raise "match not found for {" unless depth.zero?
from + s.pos - 1
end
# opening brace position from +from+ (search backwards)
def open_brace_pos(css, from, depth = 0)
s = CharStringScanner.new(css[0..from].reverse)
while (b = s.scan_next(BRACE_RE_REVERSE))
depth += (b == '{' ? +1 : -1)
break if depth.zero?
end
raise "matching { brace not found" unless depth.zero?
from - s.pos + 1
end
# insert substitutions into text at positions (Range or Fixnum)
# substitutions can be passed as array or as yields from the &block called with |substring, position, text|
# position is a range (begin..end)
def replace_substrings_at(text, positions, replacements = nil, &block)
offset = 0
positions.each_with_index do |p, i|
p = (p...p) if p.is_a?(Fixnum)
from = p.begin + offset
to = p.end + offset
p = p.exclude_end? ? (from...to) : (from..to)
# block returns the substitution, e.g.: { |text, pos| text[pos].upcase }
r = replacements ? replacements[i] : block.call(text[p], p, text)
text[p] = r
# add the change in length to offset
offset += r.size - (p.end - p.begin + (p.exclude_end? ? 0 : 1))
end
text
end
end
end
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