improve tokenizer
remove unused argument
process tabs
change ExpressionParser.tokenizer to private
remove tab processing code
remove duplicated whitespace-checking routine
add term trimming code
add union, from, "," operator and adjust operators' precedence
generalize function parsing. function arguments are moved from function term to expression stack. This code cannot process multiple arguments yet.
Merge branch 'master' of github.com:araqne/logdb into improved_tokenizer
add comma operator to handle list
bugfix for unary operator - and added some tests
added nested concat function test code
added simple comma expression test.
fix bug crashing if expression begins with parenthesis
Nested comma operator
modify expression test code for simplifying type
remove unused arguments parsing code
improve tokenizer
remove unused argument