class SyntaxSuggest::ExplainSyntax

根据语法错误的来源解释语法错误

示例

source = "def foo; puts 'lol'" # Note missing end
explain ExplainSyntax.new(
  code_lines: CodeLine.from_source(source)
).call
explain.errors.first
# => "Unmatched keyword, missing `end' ?"

当无法通过词法计数确定错误时，将针对输入运行解析器并返回原始错误。

示例

source = "1 * " # Note missing a second number
explain ExplainSyntax.new(
  code_lines: CodeLine.from_source(source)
).call
explain.errors.first
# => "syntax error, unexpected end-of-input"

常量

INVERSE

公共类方法

new (code_lines:)

源代码

# File lib/syntax_suggest/explain_syntax.rb, line 54
def initialize(code_lines:)
  @code_lines = code_lines
  @left_right = LeftRightLexCount.new
  @missing = nil
end

公共实例方法

call ()

源代码

# File lib/syntax_suggest/explain_syntax.rb, line 60
def call
  @code_lines.each do |line|
    line.lex.each do |lex|
      @left_right.count_lex(lex)
    end
  end

  self
end

errors ()

源代码

# File lib/syntax_suggest/explain_syntax.rb, line 109
def errors
  if missing.empty?
    return GetParseErrors.errors(@code_lines.map(&:original).join).uniq
  end

  missing.map { |miss| why(miss) }
end

返回语法错误消息的数组

如果找不到缺失的配对，则回退到原始错误消息

missing ()

源代码

# File lib/syntax_suggest/explain_syntax.rb, line 79
def missing
  @missing ||= @left_right.missing
end

返回缺失元素的数组

例如，这

ExplainSyntax.new(code_lines: lines).missing
# => ["}"]

将指示源代码中缺少 ‘}` 字符

why (miss)

源代码

# File lib/syntax_suggest/explain_syntax.rb, line 91
def why(miss)
  case miss
  when "keyword"
    "Unmatched `end', missing keyword (`do', `def`, `if`, etc.) ?"
  when "end"
    "Unmatched keyword, missing `end' ?"
  else
    inverse = INVERSE.fetch(miss) {
      raise "Unknown explain syntax char or key: #{miss.inspect}"
    }
    "Unmatched `#{inverse}', missing `#{miss}' ?"
  end
end

将缺失的字符串转换为人类可理解的解释。

示例

explain.why("}")
# => "Unmatched `{', missing `}' ?"