Name Rascal/Libraries/Prelude/ParseTree/parse

Synopsis Parse input text (from a string or a location) and return a parse tree.

Function

1. &T<:Tree parse(type[&T<:Tree] begin, str input)
2. &T<:Tree parse(type[&T<:Tree] begin, str input, loc origin)
3. &T<:Tree parse(type[&T<:Tree] begin, loc input)

Usage import ParseTree;

Description

1. Parse a string and return a parse tree.
2. Parse a string and return a parse tree, origin defines the original location of the input.
3. Parse the contents of resource input and return a parse tree.

Examples

rascal>import demo::lang::Exp::Concrete::NoLayout::Syntax;
ok
rascal>import ParseTree;
ok

Seeing that parse returns a parse tree:

rascal>parse(#Exp, "2+3");
sort("Exp"): `2+3`
Tree: appl(prod(sort("Exp"),[sort("Exp"),layouts("default"),lit("+"),layouts("default"),sort("Exp")],{assoc(left())}),[appl(prod(sort("Exp"),[lex("IntegerLiteral")],{}),[appl(prod(lex("IntegerLiteral"),[iter(\char-class([range(48,57)]))],{}),[appl(regular(iter(\char-class([range(48,57)]))),[char(50)])[@loc=|file://-|(0,1,<1,0>,<1,1>)]])[@loc=|file://-|(0,1,<1,0>,<1,1>)]])[@loc=|file://-|(0,1,<1,0>,<1,1>)],appl(prod(layouts("default"),[],{}),[])[@loc=|file://-|(1,0,<1,1>,<1,1>)],appl(prod(lit("+"),[\char-class([range(43,43)])],{}),[char(43)]),appl(prod(layouts("default"),[],{}),[])[@loc=|file://-|(2,0,<1,2>,<1,2>)],appl(prod(sort("Exp"),[lex("IntegerLiteral")],{}),[appl(prod(lex("IntegerLiteral"),[iter(\char-class([range(48,57)]))],{}),[appl(regular(iter(\char-class([range(48,57)]))),[char(51)])[@loc=|file://-|(2,1,<1,2>,<1,3>)]])[@loc=|file://-|(2,1,<1,2>,<1,3>)]])[@loc=|file://-|(2,1,<1,2>,<1,3>)]])[@loc=|file://-|(0,3,<1,0>,<1,3>)]

Catching a parse error:

rascal>import IO;
ok
rascal>try {
>>>>>>>  Exp e = parse(#Exp, "2@3");
>>>>>>>}
>>>>>>>catch ParseError(loc l): {
>>>>>>>  println("I found a parse error at line <l.begin.line>, column <l.begin.column>");
>>>>>>>}
I found a parse error at line 1, column 1
ok

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