Accessing rule return values from contexts

I'm using this example code to better understand ANTLR. From what I understand the row rule returns a Map<String,String> values. The rows label inside the file rule collects all the RowContext objects. From the for-each loop in the file rule, is there a way to access the Map<String,String> values returned by the row rule?

row

Map<String,String> values

rows

file

file

Map<String,String> values

row

If not, how can I achieve accessing all of the row rules' Map<String,String> values from the file rule?

row

Map<String,String> values

file

Snippet of the code:

/** Derived from rule "file : hdr row+ ;" */
file
locals [int i=0]
: hdr ( rows+=row[$hdr.text.split(",")] {$i++;} )+
{
System.out.println($i+" rows");
for (RowContext r : $rows) {
System.out.println("row token interval: "+r.getSourceInterval());
}
}
;

hdr : row[null] {System.out.println("header: '"+$text.trim()+"'");} ;

/** Derived from rule "row : field (',' field)* 'r'? 'n' ;" */
row[String columns] returns [Map<String,String> values]
locals [int col=0]
@init {
$values = new HashMap<String,String>();
}
@after {
if ($values!=null && $values.size()>0) {
System.out.println("values = "+$values);
}
}


1 Answer
1

Have a look in the generated CSVParser.java. You can find your inline code in this generated file. If you want to access the values, just access the field values of RowContext.

CSVParser.java

values

RowContext

for (RowContext r : $rows) {
System.out.println("row token interval: "+r.getSourceInterval());
System.out.println("values: "+r.values);
}


However I recommend not to use inline code in a parser grammar. ANTLR generates a Visitor and a Listener for you. Listener/Visitor-Code is compiled just in time (if you use an appropriate IDE) while generator inline code is not compiled until generation time.

Visitor

Listener

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