prometheus/rules/lexer.l
Brian Brazil c3a2b63fe9 Add stddev and stdvar aggregation functions.
This adds the population standard deviation and
variance as aggregation functions, useful for
spotting how many standard deviations some samples
are from the mean.
2015-04-17 00:30:03 +01:00

119 lines
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/* Copyright 2013 The Prometheus Authors
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License. */
%{
package rules
import (
"fmt"
"strconv"
"strings"
clientmodel "github.com/prometheus/client_golang/model"
)
// Lex is called by the parser generated by "go tool yacc" to obtain each
// token. The method is opened before the matching rules block and closed at
// the end of the file.
func (lexer *RulesLexer) Lex(lval *yySymType) int {
// Internal lexer states.
const (
S_INITIAL = iota
S_COMMENTS
)
// We simulate multiple start symbols for closely-related grammars via dummy tokens. See
// http://www.gnu.org/software/bison/manual/html_node/Multiple-start_002dsymbols.html
// Reason: we want to be able to parse lists of named rules as well as single expressions.
if lexer.startToken != 0 {
startToken := lexer.startToken
lexer.startToken = 0
return startToken
}
c := lexer.current
currentState := 0
if lexer.empty {
c, lexer.empty = lexer.getChar(), false
}
%}
D [0-9]
L [a-zA-Z_]
M [a-zA-Z_:]
U [smhdwy]
FLOAT ({D}*\.?{D}+|{D}+\.?{D}*){EXPONENT}?|[+-]?[iI][nN][fF]|[nN][aA][nN]
EXPONENT [eE][-+]?[0-9]+
STR \"(\\.|[^\\"])*\"|\'(\\.|[^\\'])*\'
%x S_COMMENTS
%yyc c
%yyn c = lexer.getChar()
%yyt currentState
%%
lexer.buf = lexer.buf[:0] // The code before the first rule executed before every scan cycle (rule #0 / state 0 action)
"/*" currentState = S_COMMENTS
<S_COMMENTS>"*/" currentState = S_INITIAL
<S_COMMENTS>.|\n /* ignore chars within multi-line comments */
\/\/[^\r\n]*\n /* gobble up one-line comments */
ALERT|alert return ALERT
IF|if return IF
FOR|for return FOR
WITH|with return WITH
SUMMARY|summary return SUMMARY
DESCRIPTION|description return DESCRIPTION
PERMANENT|permanent return PERMANENT
BY|by return GROUP_OP
ON|on return MATCH_OP
GROUP_LEFT|GROUP_RIGHT lval.str = lexer.token(); return MATCH_MOD
group_left|group_right lval.str = strings.ToUpper(lexer.token()); return MATCH_MOD
KEEPING_EXTRA|keeping_extra return KEEPING_EXTRA
OFFSET|offset return OFFSET
AVG|SUM|MAX|MIN|COUNT|STDVAR|STDDEV lval.str = lexer.token(); return AGGR_OP
avg|sum|max|min|count|stdvar|stddev lval.str = strings.ToUpper(lexer.token()); return AGGR_OP
\<|>|AND|OR|and|or lval.str = strings.ToUpper(lexer.token()); return CMP_OP
==|!=|>=|<=|=~|!~ lval.str = lexer.token(); return CMP_OP
[+\-] lval.str = lexer.token(); return ADDITIVE_OP
[*/%] lval.str = lexer.token(); return MULT_OP
{FLOAT} num, err := strconv.ParseFloat(lexer.token(), 64);
if (err != nil && err.(*strconv.NumError).Err == strconv.ErrSyntax) {
panic("Invalid float")
}
lval.num = clientmodel.SampleValue(num)
return NUMBER
{D}+{U} lval.str = lexer.token(); return DURATION
{L}({L}|{D})* lval.str = lexer.token(); return IDENTIFIER
{M}({M}|{D})* lval.str = lexer.token(); return METRICNAME
{STR} lval.str = lexer.token()[1:len(lexer.token()) - 1]; return STRING
[{}\[\]()=,] return int(lexer.buf[0])
[\t\n\r ] /* gobble up any whitespace */
%%
lexer.empty = true
return int(c)
}