Class: MongoRecord::SQL::Parser
Overview
Only parses simple WHERE clauses right now. The parser returns a query Hash suitable for use by Mongo.
Class Method Summary collapse
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.parse_where(sql, remove_table_names = false) ⇒ Object
Parse a WHERE clause (without the “WHERE”) ane return a query Hash suitable for use by Mongo.
Instance Method Summary collapse
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#initialize(tokenizer) ⇒ Parser
constructor
A new instance of Parser.
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#parse_where(remove_table_names = false) ⇒ Object
Parse a WHERE clause (without the “WHERE”) and return a query Hash suitable for use by Mongo.
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#regexp_from_string(str) ⇒ Object
Given a regexp string like ‘%foo%’, return a Regexp object.
Constructor Details
#initialize(tokenizer) ⇒ Parser
Returns a new instance of Parser.
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# File 'lib/mongo_record/sql.rb', line 135 def initialize(tokenizer) @tokenizer = tokenizer end |
Class Method Details
.parse_where(sql, remove_table_names = false) ⇒ Object
Parse a WHERE clause (without the “WHERE”) ane return a query Hash suitable for use by Mongo.
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# File 'lib/mongo_record/sql.rb', line 131 def self.parse_where(sql, remove_table_names=false) Parser.new(Tokenizer.new(sql)).parse_where(remove_table_names) end |
Instance Method Details
#parse_where(remove_table_names = false) ⇒ Object
Parse a WHERE clause (without the “WHERE”) and return a query Hash suitable for use by Mongo.
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# File 'lib/mongo_record/sql.rb', line 158 def parse_where(remove_table_names=false) filters = {} done = false while !done && @tokenizer.more? name = @tokenizer.next_token raise "sql parser can't handle nested stuff yet: #{@tokenizer.sql}" if name == '(' name.sub!(/.*\./, '') if remove_table_names # Remove "schema.table." from "schema.table.col" op = @tokenizer.next_token op += (' ' + @tokenizer.next_token) if op.downcase == 'not' op = op.downcase val = @tokenizer.next_token case op when "=" filters[name] = val when "<" filters[name] = { :$lt => val } when "<=" filters[name] = { :$lte => val } when ">" filters[name] = { :$gt => val } when ">=" filters[name] = { :$gte => val } when "<>", "!=" filters[name] = { :$ne => val } when "like" filters[name] = regexp_from_string(val) when "in" raise "'in' must be followed by a list of values: #{@tokenizer.sql}" unless val == '(' filters[name] = { :$in => read_array } when "between" conjunction = @tokenizer.next_token.downcase raise "syntax error: expected 'between X and Y', but saw '" + conjunction + "' instead of 'and'" unless conjunction == 'and' val2 = @tokenizer.next_token val2, val = val, val2 if val > val2 # Make sure val <= val2 filters[name] = { :$gte => val, :$lte => val2 } else raise "can't handle sql operator [#{op}] yet: #{@tokenizer.sql}" end break unless @tokenizer.more? tok = @tokenizer.next_token.downcase case tok when 'and' next when 'or' raise "sql parser can't handle ors yet: #{@tokenizer.sql}" when 'order', 'group', 'limit' @tokenizer.add_extra_token(tok) done = true else raise "can't handle [#{tok}] yet" end end filters end |
#regexp_from_string(str) ⇒ Object
Given a regexp string like ‘%foo%’, return a Regexp object. We set Regexp::IGNORECASE so that all regex matches are case-insensitive.
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# File 'lib/mongo_record/sql.rb', line 141 def regexp_from_string(str) if str[0,1] == '%' str = str[1..-1] else str = '^' + str end if str[-1,1] == '%' str = str[0..-2] else str = str + '$' end Regexp.new(str, Regexp::IGNORECASE) end |