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Diffstat (limited to 'lib/coderay/scanners/lua.rb')
| -rw-r--r-- | lib/coderay/scanners/lua.rb | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb new file mode 100644 index 0000000..fb1e45a --- /dev/null +++ b/lib/coderay/scanners/lua.rb @@ -0,0 +1,280 @@ +# encoding: utf-8 + +module CodeRay +module Scanners + + # Scanner for the Lua[http://lua.org] programming lanuage. + # + # The language’s complete syntax is defined in + # {the Lua manual}[http://www.lua.org/manual/5.2/manual.html], + # which is what this scanner tries to conform to. + class Lua < Scanner + + register_for :lua + file_extension 'lua' + title 'Lua' + + # Keywords used in Lua. + KEYWORDS = %w[and break do else elseif end + for function goto if in + local not or repeat return + then until while + ] + + # Constants set by the Lua core. + PREDEFINED_CONSTANTS = %w[false true nil] + + # The expressions contained in this array are parts of Lua’s `basic' + # library. Although it’s not entirely necessary to load that library, + # it is highly recommended and one would have to provide own implementations + # of some of these expressions if one does not do so. They however aren’t + # keywords, neither are they constants, but nearly predefined, so they + # get tagged as `predefined' rather than anything else. + # + # This list excludes values of form `_UPPERCASE' because the Lua manual + # requires such identifiers to be reserved by Lua anyway and they are + # highlighted directly accordingly, without the need for specific + # identifiers to be listed here. + PREDEFINED_EXPRESSIONS = %w[ + assert collectgarbage dofile error getmetatable + ipairs load loadfile next pairs pcall print + rawequal rawget rawlen rawset select setmetatable + tonumber tostring type xpcall + ] + + # Automatic token kind selection for normal words. + IDENT_KIND = CodeRay::WordList.new(:ident). + add(KEYWORDS, :keyword). + add(PREDEFINED_CONSTANTS, :predefined_constant). + add(PREDEFINED_EXPRESSIONS, :predefined) + + protected + + # Scanner initialization. + def setup + @state = :initial + @brace_depth = 0 + end + + # CodeRay entry hook. Starts parsing. + def scan_tokens(encoder, options) + state = options[:state] || @state + brace_depth = @brace_depth + num_equals = nil + + until eos? + case state + + when :initial + if match = scan(/\-\-\[\=*\[/) #--[[ long (possibly multiline) comment ]] + num_equals = match.count("=") # Number must match for comment end + encoder.begin_group(:comment) + encoder.text_token(match, :delimiter) + state = :long_comment + + elsif match = scan(/--.*$/) # --Lua comment + encoder.text_token(match, :comment) + + elsif match = scan(/\[=*\[/) # [[ long (possibly multiline) string ]] + num_equals = match.count("=") # Number must match for comment end + encoder.begin_group(:string) + encoder.text_token(match, :delimiter) + state = :long_string + + elsif match = scan(/::\s*[a-zA-Z_][a-zA-Z0-9_]+\s*::/) # ::goto_label:: + encoder.text_token(match, :label) + + elsif match = scan(/_[A-Z]+/) # _UPPERCASE are names reserved for Lua + encoder.text_token(match, :predefined) + + elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # Normal letters (or letters followed by digits) + kind = IDENT_KIND[match] + + # Extra highlighting for entities following certain keywords + if kind == :keyword and match == "function" + state = :function_expected + elsif kind == :keyword and match == "goto" + state = :goto_label_expected + elsif kind == :keyword and match == "local" + state = :local_var_expected + end + + encoder.text_token(match, kind) + + elsif match = scan(/\{/) # Opening table brace { + encoder.begin_group(:map) + encoder.text_token(match, brace_depth >= 1 ? :inline_delimiter : :delimiter) + brace_depth += 1 + state = :map + + elsif match = scan(/\}/) # Closing table brace } + if brace_depth == 1 + brace_depth = 0 + encoder.text_token(match, :delimiter) + encoder.end_group(:map) + elsif brace_depth == 0 # Mismatched brace + encoder.text_token(match, :error) + else + brace_depth -= 1 + encoder.text_token(match, :inline_delimiter) + encoder.end_group(:map) + state = :map + end + + elsif match = scan(/["']/) # String delimiters " and ' + encoder.begin_group(:string) + encoder.text_token(match, :delimiter) + start_delim = match + state = :string + + # ↓Prefix hex number ←|→ decimal number + elsif match = scan(/-? (?:0x\h* \. \h+ (?:p[+\-]?\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?)/ix) # hexadecimal constants have no E power, decimal ones no P power + encoder.text_token(match, :float) + + # ↓Prefix hex number ←|→ decimal number + elsif match = scan(/-? (?:0x\h+ (?:p[+\-]?\d+)? | \d+ (?:e[+\-]?\d+)?)/ix) # hexadecimal constants have no E power, decimal ones no P power + encoder.text_token(match, :integer) + + elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\[\]:;,] | \.(?!\d)/x) # Operators + encoder.text_token(match, :operator) + + elsif match = scan(/\s+/) # Space + encoder.text_token(match, :space) + + else # Invalid stuff. Note that Lua doesn’t accept multibyte chars outside of strings, hence these are also errors. + encoder.text_token(getch, :error) + end + + # It may be that we’re scanning a full-blown subexpression of a table + # (tables can contain full expressions in parts). + # If this is the case, return to :map scanning state. + state = :map if state == :initial && brace_depth >= 1 + + when :function_expected + if match = scan(/\(.*?\)/m) # x = function() # "Anonymous" function without explicit name + encoder.text_token(match, :operator) + state = :initial + elsif match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* [\.\:]/x) # function tbl.subtbl.foo() | function tbl:foo() # Colon only allowed as last separator + encoder.text_token(match, :ident) + elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # function foo() + encoder.text_token(match, :function) + state = :initial + elsif match = scan(/\s+/) # Between the `function' keyword and the ident may be any amount of whitespace + encoder.text_token(match, :space) + else + encoder.text_token(getch, :error) + state = :initial + end + + when :goto_label_expected + if match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) + encoder.text_token(match, :label) + state = :initial + elsif match = scan(/\s+/) # Between the `goto' keyword and the label may be any amount of whitespace + encoder.text_token(match, :space) + else + encoder.text_token(getch, :error) + end + + when :local_var_expected + if match = scan(/function/) # local function ... + encoder.text_token(match, :keyword) + state = :function_expected + elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) + encoder.text_token(match, :local_variable) + elsif match = scan(/,/) + encoder.text_token(match, :operator) + elsif match = scan(/\=/) + encoder.text_token(match, :operator) + # After encountering the equal sign, arbitrary expressions are + # allowed again, so just return to the main state for further + # parsing. + state = :initial + elsif match = scan(/\n/) + encoder.text_token(match, :space) + state = :initial + elsif match = scan(/\s+/) + encoder.text_token(match, :space) + else + encoder.text_token(getch, :error) + end + + when :long_comment + if match = scan(/.*?(?=\]={#{num_equals}}\])/m) + encoder.text_token(match, :content) + + delim = scan(/\]={#{num_equals}}\]/) + encoder.text_token(delim, :delimiter) + else # No terminator found till EOF + encoder.text_token(rest, :error) + terminate + end + encoder.end_group(:comment) + state = :initial + + when :long_string + if match = scan(/.*?(?=\]={#{num_equals}}\])/m) # Long strings do not interpret any escape sequences + encoder.text_token(match, :content) + + delim = scan(/\]={#{num_equals}}\]/) + encoder.text_token(delim, :delimiter) + else # No terminator found till EOF + encoder.text_token(rest, :error) + terminate + end + encoder.end_group(:string) + state = :initial + + when :string + if match = scan(/[^\\#{start_delim}\n]+/) # Everything except \ and the start delimiter character is string content (newlines are only allowed if preceeded by \ or \z) + encoder.text_token(match, :content) + elsif match = scan(/\\(?:['"abfnrtv\\]|z\s*|x\h\h|\d{1,3}|\n)/m) + encoder.text_token(match, :char) + elsif match = scan(Regexp.compile(start_delim)) + encoder.text_token(match, :delimiter) + encoder.end_group(:string) + state = :initial + elsif match = scan(/\n/) # Lua forbids unescaped newlines in normal non-long strings + encoder.text_token("\\n\n", :error) # Visually appealing error indicator--otherwise users may wonder whether the highlighter cannot highlight multine strings + encoder.end_group(:string) + state = :initial + else + encoder.text_token(getch, :error) + end + + when :map + if match = scan(/[,;]/) + encoder.text_token(match, :operator) + elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]* (?=\s*=)/x) + encoder.text_token(match, :key) + encoder.text_token(scan(/\s+/), :space) if check(/\s+/) + encoder.text_token(scan(/\=/), :operator) + state = :initial + elsif match = scan(/\s+/m) + encoder.text_token(match, :space) + else + # Note this clause doesn’t advance the scan pointer, it’s a kind of + # "retry with other options" (the :initial state then of course + # advances the pointer). + state = :initial + end + else + raise + end + + end + + if options[:keep_state] + @state = state + end + + encoder.end_group :string if [:string].include? state + brace_depth.times { encoder.end_group :map } + + encoder + end + + end + +end +end |