transmute parsing error

[hscells]

Not sure what the original query was...

stack trace:

POST /api/query2cqr HTTP/1.1
Host: localhost:8000
Accept: */*
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Content-Length: 18
Content-Type: application/x-www-form-urlencoded
Origin: https://ielab-sysrev2.uqcloud.net
Referer: https://ielab-sysrev2.uqcloud.net/plugin/queryvis
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin

runtime error: index out of range [0] with length 0
/usr/lib/go-1.13/src/runtime/panic.go:75 (0x839162)
        goPanicIndex: panic(boundsError{x: int64(x), signed: true, y: y, code: boundsIndex})
/home/harry/go/src/github.com/hscells/transmute/parser/pubmed.go:318 (0xdc657d)
        PubMedTransformer.ParseInfixKeywords: if prefix[0] == "(" && prefix[len(prefix)-1] == ")" {
/home/harry/go/src/github.com/hscells/transmute/parser/pubmed.go:197 (0xdc47c4)
        PubMedTransformer.TransformNested: return t.ParseInfixKeywords(query, mapping)
/home/harry/go/src/github.com/hscells/transmute/parser/parser.go:32 (0xdc3eef)
        QueryParser.Parse: return q.Parser.TransformNested(ast.Value, q.FieldMapping)
/home/harry/go/src/github.com/hscells/transmute/pipeline/pipeline.go:80 (0xdd0a72)
        TransmutePipeline.Execute: boolQuery := p.Parser.Parse(ast)
/home/harry/go/src/github.com/ielab/searchrefiner/api.go:638 (0x11182bf)
        ApiQuery2CQR: cq, err := compiler.Execute(rawQuery)
/home/harry/go/src/github.com/gin-gonic/gin/context.go:165 (0xd8e37a)
        (*Context).Next: c.handlers[c.index](c)
/home/harry/go/src/github.com/gin-contrib/gzip/handler.go:60 (0xda4263)
        (*gzipHandler).Handle: c.Next()
/home/harry/go/src/github.com/gin-gonic/gin/context.go:165 (0xd8e37a)
        (*Context).Next: c.handlers[c.index](c)
/home/harry/go/src/github.com/ielab/searchrefiner/cmd/searchrefiner/server.go:165 (0x112b241)
        main.func2: c.Next()
/home/harry/go/src/github.com/gin-gonic/gin/context.go:165 (0xd8e37a)
        (*Context).Next: c.handlers[c.index](c)
/home/harry/go/src/github.com/gin-gonic/gin/logger.go:241 (0xda14f0)
        LoggerWithConfig.func1: c.Next()
/home/harry/go/src/github.com/gin-gonic/gin/context.go:165 (0xd8e37a)
        (*Context).Next: c.handlers[c.index](c)
/home/harry/go/src/github.com/gin-gonic/gin/recovery.go:83 (0xda23c3)
        RecoveryWithWriter.func1: c.Next()
/home/harry/go/src/github.com/gin-gonic/gin/context.go:165 (0xd8e37a)
        (*Context).Next: c.handlers[c.index](c)
/home/harry/go/src/github.com/gin-gonic/gin/logger.go:241 (0xda14f0)
        LoggerWithConfig.func1: c.Next()
/home/harry/go/src/github.com/gin-gonic/gin/context.go:165 (0xd8e37a)
        (*Context).Next: c.handlers[c.index](c)
/home/harry/go/src/github.com/gin-gonic/gin/gin.go:420 (0xd985d0)
        (*Engine).handleHTTPRequest: c.Next()
/home/harry/go/src/github.com/gin-gonic/gin/gin.go:376 (0xd97d3c)
        (*Engine).ServeHTTP: engine.handleHTTPRequest(c)
/usr/lib/go-1.13/src/net/http/server.go:2802 (0xb046b3)
        serverHandler.ServeHTTP: handler.ServeHTTP(rw, req)
/usr/lib/go-1.13/src/net/http/server.go:1890 (0xafff54)
        (*conn).serve: serverHandler{c.server}.ServeHTTP(w, w.req)
/usr/lib/go-1.13/src/runtime/asm_amd64.s:1357 (0x8685b0)
        goexit: BYTE    $0x90   // NOP

[GIN-debug] [WARNING] Headers were already written. Wanted to override status code 200 with 500