// Parse a single Expression, returning a Tree
//
// ParseExpression("5 * toint(item_name)")
//
func ParseExpression(expressionText string) (*Tree, error) {
l := lex.NewLexer(expressionText, lex.LogicalExpressionDialect)
pager := NewLexTokenPager(l)
t := NewTree(pager)
pager.end = lex.TokenEOF
err := t.BuildTree(true)
return t, err
}
func verifyTokens(t *testing.T, sql string, tokens []lex.Token) {
l := lex.NewLexer(sql, InfluxQlDialect)
for _, goodToken := range tokens {
tok := l.NextToken()
u.Debugf("%#v %#v", tok, goodToken)
assert.Equalf(t, tok.V, goodToken.V, "has='%v' want='%v'", tok.V, goodToken.V)
assert.Equalf(t, tok.T, goodToken.T, "has='%v' want='%v'", tok.V, goodToken.V)
}
}
// Parse a single Expression, returning a Tree
//
// ParseExpression("5 * toint(item_name)")
//
func ParseExpression(expressionText string) (*Tree, error) {
l := lex.NewLexer(expressionText, lex.LogicalExpressionDialect)
pager := NewLexTokenPager(l)
t := NewTree(pager)
// Parser panics on unexpected syntax, convert this into an err
err := t.BuildTree(true)
return t, err
}
func main() {
/* Many *ql languages support some type of columnar layout such as:
name = value, name2 = value2
*/
l := lex.NewLexer(`
SUBSCRIBETO
count(x), Name
FROM ourstream
WHERE
k = REPLACE(LOWER(Name),"cde","xxx");`, ourDialect)
verifyLexerTokens(l,
[]lex.Token{
Tok(TokenSubscribeTo, "SUBSCRIBETO"),
Tok(lex.TokenUdfExpr, "count"),
Tok(lex.TokenLeftParenthesis, "("),
Tok(lex.TokenIdentity, "x"),
Tok(lex.TokenRightParenthesis, ")"),
Tok(lex.TokenComma, ","),
Tok(lex.TokenIdentity, "Name"),
Tok(lex.TokenFrom, "FROM"),
Tok(lex.TokenIdentity, "ourstream"),
Tok(lex.TokenWhere, "WHERE"),
Tok(lex.TokenIdentity, "k"),
Tok(lex.TokenEqual, "="),
Tok(lex.TokenUdfExpr, "REPLACE"),
Tok(lex.TokenLeftParenthesis, "("),
Tok(lex.TokenUdfExpr, "LOWER"),
Tok(lex.TokenLeftParenthesis, "("),
Tok(lex.TokenIdentity, "Name"),
Tok(lex.TokenRightParenthesis, ")"),
Tok(lex.TokenComma, ","),
Tok(lex.TokenValue, "cde"),
Tok(lex.TokenComma, ","),
Tok(lex.TokenValue, "xxx"),
Tok(lex.TokenRightParenthesis, ")"),
Tok(lex.TokenEOS, ";"),
})
}
// Parses string query
func Parse(query string) (*Ast, error) {
l := lex.NewLexer(query, InfluxQlDialect)
p := Parser{l: l, qryText: query}
return p.parse()
}