Wolfram Language Paclet Repository
Community-contributed installable additions to the Wolfram Language
Wolfram`Parser`
ParsePosition  |
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| Bracketing a sub-parser, ParsePosition[]~~p~~ParsePosition[] | | ||||
▪
ParsePosition[]
▪
The position is a 1-based character offset into the input. The end position a closing reports is one past the last character the bracketed parser consumed, so is exactly the number of characters matched.
ParsePosition[]
end-start
▪
Bracketing yields a shape: the leading contributes start, the inner parser its value, the trailing the end. Inside a those three become successive elements; reshape with .
{start,value,end}
ParsePosition[]
ParsePosition[]
▪
This is the primitive behind source tracking. uses to record each leaf's offset span, and turns those offsets into pairs - 's LineColumn convention.
ParsePosition[]
{{startLine,startColumn},{endLine,endColumn}}
CodeParser
Examples
(2)
Basic Examples
(1)
In[1]:=
 | ParsePosition |
Out[1]=
ParserCombinator
 |
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Bracket a number parser to capture the span it covers - start , the matched text, end (one past the last digit):
1
4
In[2]:=
| Parse |
 | ParseSequence |
 | ParsePosition |
| ParseRegex |
| ParsePosition |
Out[2]=
{1,123,4}
Because it consumes nothing, a after a whitespace skip reports the position the next token actually starts at. Reshape with to keep just the triple:
ParsePosition[]
{start,value,end}
In[3]:=
ws=
[WhitespaceCharacter];spanned=
ws~~
[]~~
["[0-9]+"]~~
[],Function[{skip,s,v,e},{s,v,e}];
[spanned," 123"]
| ParseMany |
 | ParseCharacter |
| ParseAction |
 | ParsePosition |
| ParseRegex |
| ParsePosition |
| Parse |
Out[3]=
{3,123,6}
The start jumped to , past the two leading spaces.
3
Properties & Relations
(1)
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""