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zclsyntax: decoding of quoted string literal escape sequences

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This commit is contained in:
Martin Atkins 2017-05-30 19:38:31 -07:00
parent f94c89a6a5
commit f8bdda5ab9
2 changed files with 182 additions and 3 deletions
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91
zcl/zclsyntax/parser.go
View File

@ -1,9 +1,11 @@
package zclsyntax
import (
"bufio"
"bytes"
"fmt"
"github.com/apparentlymart/go-textseg/textseg"
"github.com/zclconf/go-zcl/zcl"
)
@ -277,9 +279,9 @@ Token:
break Token
case TokenQuotedLit:
// TODO: Remove any escape sequences from the string, once we
// have a function with which to do that.
ret.Write(tok.Bytes)
s, sDiags := p.decodeQuotedLit(tok)
diags = append(diags, sDiags...)
ret.WriteString(s)
case TokenTemplateControl, TokenTemplateInterp:
which := "$"
@ -328,6 +330,89 @@ Token:
return ret.String(), zcl.RangeBetween(oQuote.Range, cQuote.Range), diags
}
// decodeQuotedLit processes the given TokenQuotedLit token as if it were
// a string literal appearing in quotes, returning the string resulting from
// resolving any escape sequences.
//
// If any error diagnostics are returned, the returned string may be incomplete
// or otherwise invalid.
func (p *parser) decodeQuotedLit(tok Token) (string, zcl.Diagnostics) {
if tok.Type != TokenQuotedLit {
panic("decodeQuotedLit can only be used with TokenQuotedLit tokens")
}
var diags zcl.Diagnostics
ret := make([]byte, 0, len(tok.Bytes))
sc := bufio.NewScanner(bytes.NewReader(tok.Bytes))
sc.Split(textseg.ScanGraphemeClusters)
escaping := rune(0)
pos := tok.Range.Start
for sc.Scan() {
switch escaping {
case '\\':
escaping = 0
ty := sc.Text()
switch ty {
case "n":
ret = append(ret, 10)
case "r":
ret = append(ret, 13)
case "t":
ret = append(ret, 9)
// TODO: numeric character escapes with \uXXXX
default:
diags = append(diags, &zcl.Diagnostic{
Severity: zcl.DiagError,
Summary: "Invalid escape sequence",
Detail: fmt.Sprintf("The sequence \"\\%s\" is not a recognized escape sequence.", ty),
Subject: &zcl.Range{
Filename: tok.Range.Filename,
Start: zcl.Pos{
Line: pos.Line,
Column: pos.Column - 1, // safe because we know the previous character must be a backslash
Byte: pos.Byte - 1,
},
End: zcl.Pos{
Line: pos.Line,
Column: pos.Column + 1, // safe because we know the previous character must be a backslash
Byte: pos.Byte + len(ty),
},
},
})
ret = append(ret, sc.Bytes()...)
}
case '$', '!':
bytes := sc.Bytes()
if len(bytes) != 1 || bytes[0] == byte(escaping) {
ret = append(ret, byte(escaping))
}
ret = append(ret, bytes...)
default:
switch sc.Text() {
case "\\":
escaping = '\\'
case "$":
escaping = '$'
case "!":
escaping = '!'
default:
ret = append(ret, sc.Bytes()...)
}
}
// Literal newlines cannot appear in quoted literals, so it's safe
// to just increment Column and Byte in our position.
pos.Column++
pos.Byte += len(sc.Bytes())
}
return string(ret), diags
}
// recover seeks forward in the token stream until it finds TokenType "end",
// then returns with the peeker pointed at the following token.
//

94
zcl/zclsyntax/parser_test.go
View File

@ -219,6 +219,100 @@ block "valid" {}
},
},
},
{
`block "f\o" {}`,
1, // \o is not a valid escape sequence
&Body{
Attributes: Attributes{},
Blocks: Blocks{
&Block{
Type: "block",
Labels: []string{"fo"},
Body: nil,
TypeRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 1, Byte: 0},
End: zcl.Pos{Line: 1, Column: 6, Byte: 5},
},
LabelRanges: []zcl.Range{
{
Start: zcl.Pos{Line: 1, Column: 7, Byte: 6},
End: zcl.Pos{Line: 1, Column: 12, Byte: 11},
},
},
OpenBraceRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 1, Byte: 0},
End: zcl.Pos{Line: 1, Column: 6, Byte: 5},
},
CloseBraceRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 1, Byte: 0},
End: zcl.Pos{Line: 1, Column: 6, Byte: 5},
},
},
},
SrcRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 1, Byte: 0},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
EndRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 15, Byte: 14},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
},
},
{
`block "f\n" {}`,
0,
&Body{
Attributes: Attributes{},
Blocks: Blocks{
&Block{
Type: "block",
Labels: []string{"f\n"},
Body: &Body{
Attributes: Attributes{},
Blocks: Blocks{},
SrcRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 13, Byte: 12},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
EndRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 15, Byte: 14},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
},
TypeRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 1, Byte: 0},
End: zcl.Pos{Line: 1, Column: 6, Byte: 5},
},
LabelRanges: []zcl.Range{
{
Start: zcl.Pos{Line: 1, Column: 7, Byte: 6},
End: zcl.Pos{Line: 1, Column: 12, Byte: 11},
},
},
OpenBraceRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 13, Byte: 12},
End: zcl.Pos{Line: 1, Column: 14, Byte: 13},
},
CloseBraceRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 14, Byte: 13},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
},
},
SrcRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 1, Byte: 0},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
EndRange: zcl.Range{
Start: zcl.Pos{Line: 1, Column: 15, Byte: 14},
End: zcl.Pos{Line: 1, Column: 15, Byte: 14},
},
},
},
}
prettyConfig := &pretty.Config{