mirror of
https://github.com/danog/liquid.git
synced 2024-11-30 07:08:58 +01:00
86 lines
2.5 KiB
Go
86 lines
2.5 KiB
Go
package parser
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import (
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"fmt"
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"regexp"
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"strings"
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)
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// Scan breaks a string into a sequence of Tokens.
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func Scan(data string, loc SourceLoc, delims []string) (tokens []Token) {
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// Apply defaults
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if len(delims) != 4 {
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delims = []string{"{{", "}}", "{%", "%}"}
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}
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tokenMatcher := formTokenMatcher(delims)
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// TODO error on unterminated {{ and {%
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// TODO probably an error when a tag contains a {{ or {%, at least outside of a string
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p, pe := 0, len(data)
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for _, m := range tokenMatcher.FindAllStringSubmatchIndex(data, -1) {
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ts, te := m[0], m[1]
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if p < ts {
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tokens = append(tokens, Token{Type: TextTokenType, SourceLoc: loc, Source: data[p:ts]})
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loc.LineNo += strings.Count(data[p:ts], "\n")
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}
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source := data[ts:te]
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switch {
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case data[ts:ts+len(delims[0])] == delims[0]:
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tok := Token{
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Type: ObjTokenType,
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SourceLoc: loc,
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Source: source,
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Args: data[m[2]:m[3]],
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TrimLeft: source[2] == '-',
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TrimRight: source[len(source)-3] == '-',
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}
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tokens = append(tokens, tok)
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case data[ts:ts+len(delims[2])] == delims[2]:
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tok := Token{
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Type: TagTokenType,
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SourceLoc: loc,
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Source: source,
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Name: data[m[4]:m[5]],
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TrimLeft: source[2] == '-',
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TrimRight: source[len(source)-3] == '-',
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}
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if m[6] > 0 {
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tok.Args = data[m[6]:m[7]]
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}
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tokens = append(tokens, tok)
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}
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loc.LineNo += strings.Count(source, "\n")
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p = te
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}
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if p < pe {
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tokens = append(tokens, Token{Type: TextTokenType, SourceLoc: loc, Source: data[p:]})
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}
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return tokens
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}
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func formTokenMatcher(delims []string) *regexp.Regexp {
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// On ending a tag we need to exclude anything that appears to be ending a tag that's nested
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// inside the tag. We form the exclusion expression here.
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// For example, if delims is default the exclusion expression is "[^%]|%[^}]".
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// If tagRight is "TAG!RIGHT" then expression is
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// [^T]|T[^A]|TA[^G]|TAG[^!]|TAG![^R]|TAG!R[^I]|TAG!RI[^G]|TAG!RIG[^H]|TAG!RIGH[^T]
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var exclusion []string
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for idx, val := range delims[3] {
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exclusion = append(exclusion, "[^"+string(val)+"]")
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if idx > 0 {
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exclusion[idx] = delims[3][0:idx] + exclusion[idx]
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}
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}
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tokenMatcher := regexp.MustCompile(
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fmt.Sprintf(`%s-?\s*(.+?)\s*-?%s|%s-?\s*(\w+)(?:\s+((?:%v)+?))?\s*-?%s`,
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// QuoteMeta will escape any of these that are regex commands
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regexp.QuoteMeta(delims[0]), regexp.QuoteMeta(delims[1]),
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regexp.QuoteMeta(delims[2]), strings.Join(exclusion, "|"), regexp.QuoteMeta(delims[3]),
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),
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)
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return tokenMatcher
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}
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