diff --git a/Cargo.lock b/Cargo.lock
index 0b08beb..287d818 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -29,6 +29,12 @@ version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0942ffc6dcaadf03badf6e6a2d0228460359d5e34b57ccdc720b7382dfbd5ec5"
 
+[[package]]
+name = "anyhow"
+version = "1.0.86"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3d1d046238990b9cf5bcde22a3fb3584ee5cf65fb2765f454ed428c7a0063da"
+
 [[package]]
 name = "ariadne"
 version = "0.4.1"
@@ -66,6 +72,15 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a8241f3ebb85c056b509d4327ad0358fbbba6ffb340bf388f26350aeda225b1"
 
+[[package]]
+name = "bincode"
+version = "1.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1f45e9417d87227c7a56d22e471c6206462cba514c7590c09aff4cf6d1ddcad"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "bit-set"
 version = "0.5.3"
@@ -93,6 +108,12 @@ version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
 
+[[package]]
+name = "cactus"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "acbc26382d871df4b7442e3df10a9402bf3cf5e55cbd66f12be38861425f0564"
+
 [[package]]
 name = "cc"
 version = "1.0.79"
@@ -105,6 +126,20 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "cfgrammar"
+version = "0.13.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec07af28018dd8b4b52e49eb6e57268b19dda0996d4824889eb07ee0ef67378c"
+dependencies = [
+ "indexmap",
+ "lazy_static",
+ "num-traits",
+ "regex",
+ "serde",
+ "vob",
+]
+
 [[package]]
 name = "chumsky"
 version = "0.9.3"
@@ -149,6 +184,15 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
 
+[[package]]
+name = "deranged"
+version = "0.3.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b42b6fa04a440b495c8b04d0e71b707c585f83cb9cb28cf8cd0d976c315e31b4"
+dependencies = [
+ "powerfmt",
+]
+
 [[package]]
 name = "dirs-next"
 version = "2.0.0"
@@ -191,6 +235,18 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
+[[package]]
+name = "filetime"
+version = "0.2.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ee447700ac8aa0b2f2bd7bc4462ad686ba06baa6727ac149a2d6277f0d240fd"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall 0.4.1",
+ "windows-sys",
+]
+
 [[package]]
 name = "fixedbitset"
 version = "0.4.2"
@@ -203,6 +259,15 @@ version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
 
+[[package]]
+name = "getopts"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14dbbfd5c71d70241ecf9e6f13737f7b5ce823821063188d7e46c41d371eebd5"
+dependencies = [
+ "unicode-width",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.8"
@@ -214,6 +279,15 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "grmtools-app"
+version = "0.1.0"
+dependencies = [
+ "cfgrammar",
+ "lrlex",
+ "lrpar",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.3"
@@ -357,6 +431,60 @@ dependencies = [
  "logos-codegen",
 ]
 
+[[package]]
+name = "lrlex"
+version = "0.13.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c65e01ebaccc77218ed6fa4f0053daa2124bce4e25a5e83aae0f7ccfc9cbfccb"
+dependencies = [
+ "cfgrammar",
+ "getopts",
+ "lazy_static",
+ "lrpar",
+ "num-traits",
+ "quote",
+ "regex",
+ "regex-syntax 0.8.2",
+ "serde",
+ "vergen",
+]
+
+[[package]]
+name = "lrpar"
+version = "0.13.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a4b858180a332aec09d10479a070802b13081077eb94010744bc4e3a11d9768"
+dependencies = [
+ "bincode",
+ "cactus",
+ "cfgrammar",
+ "filetime",
+ "indexmap",
+ "lazy_static",
+ "lrtable",
+ "num-traits",
+ "packedvec",
+ "regex",
+ "serde",
+ "static_assertions",
+ "vergen",
+ "vob",
+]
+
+[[package]]
+name = "lrtable"
+version = "0.13.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fcefc5628209d1b1f4b2cd0bcefd0e50be80bdf178e886cb07317f5ce4f2856"
+dependencies = [
+ "cfgrammar",
+ "fnv",
+ "num-traits",
+ "serde",
+ "sparsevec",
+ "vob",
+]
+
 [[package]]
 name = "memchr"
 version = "2.7.1"
@@ -396,12 +524,46 @@ dependencies = [
 name = "null-app"
 version = "0.1.0"
 
+[[package]]
+name = "num-conv"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"
+
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "num_threads"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c7398b9c8b70908f6371f47ed36737907c87c52af34c268fed0bf0ceb92ead9"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.17.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b7e5500299e16ebb147ae15a00a942af264cf3688f47923b8fc2cd5858f23ad3"
 
+[[package]]
+name = "packedvec"
+version = "1.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bde3c690ec20e4a2b4fb46f0289a451181eb50011a1e2acc8d85e2fde9062a45"
+dependencies = [
+ "num-traits",
+ "serde",
+]
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -502,6 +664,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5be167a7af36ee22fe3115051bc51f6e6c7054c9348e28deb4f49bd6f705a315"
 
+[[package]]
+name = "powerfmt"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
+
 [[package]]
 name = "precomputed-hash"
 version = "0.1.1"
@@ -553,6 +721,15 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "redox_syscall"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4722d768eff46b75989dd134e5c353f0d6296e5aaa3132e776cbdb56be7731aa"
+dependencies = [
+ "bitflags",
+]
+
 [[package]]
 name = "redox_users"
 version = "0.4.3"
@@ -610,6 +787,15 @@ version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
 
+[[package]]
+name = "rustc_version"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa0f585226d2e68097d4f95d113b15b83a82e819ab25717ec0590d9584ef366"
+dependencies = [
+ "semver",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.14"
@@ -637,6 +823,12 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "semver"
+version = "1.0.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61697e0a1c7e512e84a621326239844a24d8207b4669b41bc18b32ea5cbf988b"
+
 [[package]]
 name = "serde"
 version = "1.0.196"
@@ -687,6 +879,18 @@ version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "62bb4feee49fdd9f707ef802e22365a35de4b7b299de4763d44bfea899442ff9"
 
+[[package]]
+name = "sparsevec"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35df5d2e580b29f3f7ec5b4ed49b0ab3acf7f3624122b3e823cafb9630f293b8"
+dependencies = [
+ "num-traits",
+ "packedvec",
+ "serde",
+ "vob",
+]
+
 [[package]]
 name = "stacker"
 version = "0.1.15"
@@ -700,6 +904,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
 [[package]]
 name = "string_cache"
 version = "0.8.7"
@@ -755,6 +965,39 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "time"
+version = "0.3.36"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5dfd88e563464686c916c7e46e623e520ddc6d79fa6641390f2e3fa86e83e885"
+dependencies = [
+ "deranged",
+ "itoa",
+ "libc",
+ "num-conv",
+ "num_threads",
+ "powerfmt",
+ "serde",
+ "time-core",
+ "time-macros",
+]
+
+[[package]]
+name = "time-core"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef927ca75afb808a4d64dd374f00a2adf8d0fcff8e7b184af886c3c87ec4a3f3"
+
+[[package]]
+name = "time-macros"
+version = "0.2.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f252a68540fde3a3877aeea552b832b40ab9a69e318efd078774a01ddee1ccf"
+dependencies = [
+ "num-conv",
+ "time-core",
+]
+
 [[package]]
 name = "tiny-keccak"
 version = "2.0.2"
@@ -797,12 +1040,34 @@ dependencies = [
  "void",
 ]
 
+[[package]]
+name = "vergen"
+version = "8.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e27d6bdd219887a9eadd19e1c34f32e47fa332301184935c6d9bca26f3cca525"
+dependencies = [
+ "anyhow",
+ "rustversion",
+ "time",
+]
+
 [[package]]
 name = "version_check"
 version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "vob"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c058f4c41e71a043c67744cb76dcc1ae63ece328c1732a72489ccccc2dec23e6"
+dependencies = [
+ "num-traits",
+ "rustc_version",
+ "serde",
+]
+
 [[package]]
 name = "void"
 version = "1.0.2"
diff --git a/examples/grmtools-app/Cargo.toml b/examples/grmtools-app/Cargo.toml
new file mode 100644
index 0000000..703fe82
--- /dev/null
+++ b/examples/grmtools-app/Cargo.toml
@@ -0,0 +1,18 @@
+[package]
+name = "grmtools-app"
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "grmtools-app"
+path = "app.rs"
+
+[build-dependencies]
+cfgrammar = "0.13"
+lrlex = "0.13"
+lrpar = "0.13"
+
+[dependencies]
+cfgrammar = "0.13"
+lrlex = "0.13"
+lrpar = "0.13"
diff --git a/examples/grmtools-app/app.rs b/examples/grmtools-app/app.rs
new file mode 100644
index 0000000..3ca46e0
--- /dev/null
+++ b/examples/grmtools-app/app.rs
@@ -0,0 +1,29 @@
+use lrlex::lrlex_mod;
+use lrpar::lrpar_mod;
+use std::{env, fs};
+
+lrlex_mod!("json.l");
+lrpar_mod!("json.y");
+
+mod json_val;
+
+fn main() {
+    let src = fs::read_to_string(env::args().nth(1).expect("Expected file argument"))
+        .expect("Failed to read file");
+
+    let lexerdef = json_l::lexerdef();
+    let lexer = lexerdef.lexer(&src);
+    let (res, errs) = json_y::parse(&lexer);
+    for e in errs {
+        println!("{}", e.pp(&lexer, &json_y::token_epp));
+    }
+    match res {
+        Some(r) => {
+            #[cfg(debug_assertions)]
+            println!("{r:#?}");
+            #[cfg(not(debug_assertions))]
+            let _ = std::hint::black_box(r);
+        }
+        None => panic!(),
+    }
+}
diff --git a/examples/grmtools-app/build.rs b/examples/grmtools-app/build.rs
new file mode 100644
index 0000000..8608eb6
--- /dev/null
+++ b/examples/grmtools-app/build.rs
@@ -0,0 +1,26 @@
+use cfgrammar::yacc::YaccKind;
+use lrlex::CTLexerBuilder;
+use std::{env, path::PathBuf};
+
+fn main() {
+    CTLexerBuilder::new()
+        .lrpar_config(|ctp| {
+            ctp.yacckind(YaccKind::Grmtools)
+                .grammar_path("json.y")
+                .output_path(
+                    [env::var("OUT_DIR").unwrap().as_str(), "json.y.rs"]
+                        .iter()
+                        .collect::<PathBuf>(),
+                )
+                .mod_name("json_y")
+        })
+        .lexer_path("json.l")
+        .output_path(
+            [env::var("OUT_DIR").unwrap().as_str(), "json.l.rs"]
+                .iter()
+                .collect::<PathBuf>(),
+        )
+        .mod_name("json_l")
+        .build()
+        .unwrap();
+}
diff --git a/examples/grmtools-app/json.l b/examples/grmtools-app/json.l
new file mode 100644
index 0000000..750163e
--- /dev/null
+++ b/examples/grmtools-app/json.l
@@ -0,0 +1,14 @@
+%%
+"[^"]*" "STRING"
+-?(0|([1-9][0-9]*))(\.[0-9]*)?([eE][-+]?[0-9]+)? "FLOAT"
+\[ "["
+\] "]"
+\{ "{"
+\} "}"
+: ":"
+, ","
+false "FALSE"
+null "NULL"
+true "TRUE"
+[\n\r\t ]+ ;
+. "UNMATCHED"
diff --git a/examples/grmtools-app/json.y b/examples/grmtools-app/json.y
new file mode 100644
index 0000000..f9e9506
--- /dev/null
+++ b/examples/grmtools-app/json.y
@@ -0,0 +1,66 @@
+%start Object
+%expect-unused Unmatched "UNMATCHED"
+
+%%
+
+Object -> Result<Value, Box<dyn Error>>:
+    "{" ObjectMembersOpt "}" { Ok(Value::Object(HashMap::from_iter($2?))) }
+  ;
+
+ObjectMembersOpt -> Result<Vec<(String, Value)>, Box<dyn Error>>:
+    ObjectMembers { $1 }
+  | { Ok(Vec::new()) }
+  ;
+
+ObjectMembers -> Result<Vec<(String, Value)>, Box<dyn Error>>:
+    ObjectMembers "," ObjectMember { flatten($1, $3) }
+  | ObjectMember { Ok(vec![$1?]) }
+  ;
+
+ObjectMember -> Result<(String, Value), Box<dyn Error>>:
+    "STRING" ":" Member {
+      let s = $lexer.span_str($1.unwrap().span());
+      Ok((s[1..s.len() - 1].to_owned(), $3?))
+    }
+  ;
+
+Member -> Result<Value, Box<dyn Error>>:
+    "[" ArrayMembersOpt "]" { Ok(Value::Array($2?)) }
+  | "FALSE" { Ok(Value::Boolean(false)) }
+  | "FLOAT" { Ok(Value::Num($lexer.span_str($1?.span()).parse::<f64>().unwrap())) }
+  | "NULL" { Ok(Value::Null) }
+  | Object { $1 }
+  | "STRING" {
+      let s = $lexer.span_str($1.unwrap().span());
+      Ok(Value::Str(s[1..s.len() - 1].to_owned()))
+    }
+  | "TRUE" { Ok(Value::Boolean(true)) }
+  ;
+
+ArrayMembersOpt -> Result<Vec<Value>, Box<dyn Error>>:
+    ArrayMembers { $1 }
+  | { Ok(Vec::new()) }
+  ;
+
+ArrayMembers -> Result<Vec<Value>, Box<dyn Error>>:
+    ArrayMembers "," Member { flatten($1, $3) }
+  | Member { Ok(vec![$1?])}
+  ;
+
+Unmatched -> ():
+  "UNMATCHED" { }
+  ;
+
+%%
+
+use crate::json_val::Value;
+use std::{collections::HashMap, error::Error};
+
+fn flatten<T>(lhs: Result<Vec<T>, Box<dyn Error>>, rhs: Result<T, Box<dyn Error>>)
+  -> Result<Vec<T>, Box<dyn Error>>
+{
+    let mut lhs = lhs?;
+    let rhs = rhs?;
+    lhs.push(rhs);
+    Ok(lhs)
+}
diff --git a/examples/grmtools-app/json_val.rs b/examples/grmtools-app/json_val.rs
new file mode 100644
index 0000000..1bb56bd
--- /dev/null
+++ b/examples/grmtools-app/json_val.rs
@@ -0,0 +1,11 @@
+use std::collections::HashMap;
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Value {
+    Null,
+    Boolean(bool),
+    Str(String),
+    Num(f64),
+    Array(Vec<Value>),
+    Object(HashMap<String, Value>),
+}