#![feature(try_blocks)]
#[macro_use]
extern crate lazy_static;
mod parser;
use antlr_rust::common_token_stream::CommonTokenStream;
use antlr_rust::input_stream::InputStream;
use antlr_rust::parser_rule_context::ParserRuleContext;
use antlr_rust::tree::{ErrorNode, ParseTreeListener, TerminalNode};
use parser::fhirpathlexer::FHIRPathLexer;
use parser::fhirpathlistener::FHIRPathListener;
use parser::fhirpathparser::*;
struct Listener;
impl ParseTreeListener for Listener {
fn visit_terminal(&mut self, node: &TerminalNode) {}
fn visit_error_node(&mut self, node: &ErrorNode) {}
fn enter_every_rule(&mut self, ctx: &dyn ParserRuleContext) {}
fn exit_every_rule(&mut self, ctx: &dyn ParserRuleContext) {}
}
impl FHIRPathListener for Listener {
...
}
fn main() {
let input = String::from("Observation.value");
let lexer = FHIRPathLexer::new(Box::new(InputStream::new(input)));
let token_source = CommonTokenStream::new(lexer);
let mut parser = FHIRPathParser::new(Box::new(token_source));
parser.add_parse_listener(Box::new(Listener {}));
let result = parser.expression();
assert!(result.is_ok());
}
Getting error:
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', /home/alex/.cargo/registry/src/github.com-1ecc6299db9ec823/antlr-rust-0.1.1/src/parser.rs:442:79
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
1: backtrace::backtrace::trace_unsynchronized
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print_fmt
at src/libstd/sys_common/backtrace.rs:78
3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
at src/libstd/sys_common/backtrace.rs:59
4: core::fmt::write
at src/libcore/fmt/mod.rs:1076
5: std::io::Write::write_fmt
at src/libstd/io/mod.rs:1537
6: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:62
7: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:49
8: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:198
9: std::panicking::default_hook
at src/libstd/panicking.rs:217
10: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:526
11: rust_begin_unwind
at src/libstd/panicking.rs:437
12: core::panicking::panic_fmt
at src/libcore/panicking.rs:85
13: core::panicking::panic
at src/libcore/panicking.rs:50
14: core::option::Option<T>::unwrap
at /home/alex/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libcore/macros/mod.rs:10
15: antlr_rust::parser::BaseParser<Ext,T>::unroll_recursion_context
at /home/alex/.cargo/registry/src/github.com-1ecc6299db9ec823/antlr-rust-0.1.1/src/parser.rs:442
16: fhir_server_fhirpath::parser::fhirpathparser::FHIRPathParser::expression_rec
at src/parser/fhirpathparser.rs:1493
17: fhir_server_fhirpath::parser::fhirpathparser::FHIRPathParser::expression
at src/parser/fhirpathparser.rs:1097
18: fhir_server_fhirpath::main
at src/main.rs:534
19: std::rt::lang_start::{{closure}}
at /home/alex/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/rt.rs:67
20: std::rt::lang_start_internal::{{closure}}
at src/libstd/rt.rs:52
21: std::panicking::try::do_call
at src/libstd/panicking.rs:348
22: std::panicking::try
at src/libstd/panicking.rs:325
23: std::panic::catch_unwind
at src/libstd/panic.rs:394
24: std::rt::lang_start_internal
at src/libstd/rt.rs:51
25: std::rt::lang_start
at /home/alex/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/rt.rs:67
26: main
27: __libc_start_main
28: _start
Grammar taken from here: https://github.com/HL7/fhirpath.js/blob/master/src/parser/FHIRPath.g4
Parsed like:
Getting error:
rust version:
1.46.0-nightly