class SyntaxSuggest::ExplainSyntax
Explains syntax errors based on their source
example:
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' ?"
When the error cannot be determined by lexical counting then the parser is run against the input and the raw errors are returned.
Example:
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"
Constants
- INVERSE
Public Class Methods
new(code_lines:)
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# File syntax_suggest/explain_syntax.rb, line 54 def initialize(code_lines:) @code_lines = code_lines @left_right = LeftRightLexCount.new @missing = nil end
Public Instance Methods
call()
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# File 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()
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Returns an array of syntax error messages
If no missing pairs are found it falls back on the original error messages
# File 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
missing()
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Returns an array of missing elements
For example this:
ExplainSyntax.new(code_lines: lines).missing # => ["}"]
Would indicate that the source is missing a ‘}` character in the source code
# File syntax_suggest/explain_syntax.rb, line 79 def missing @missing ||= @left_right.missing end
why(miss)
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Converts a missing string to an human understandable explanation.
Example:
explain.why("}") # => "Unmatched `{', missing `}' ?"
# File 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