diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index 4d76cadf867df4dc36f55d9c3012bb91000d9304..cecc9e8c2cb32e1e507578d9fed23a5c7b6c55bb 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -4,11 +4,16 @@
"version": "2.0.0",
"tasks": [
{
- "type": "cargo",
- "subcommand": "build",
+ "type": "shell",
+ "label": "cargo check --example main_span_expr",
+ "command": "cargo check --example main_span_expr",
"problemMatcher": [
"$rustc"
- ]
+ ],
+ "group": {
+ "kind": "build",
+ "isDefault": true
+ }
}
]
}
\ No newline at end of file
diff --git a/Cargo.lock b/Cargo.lock
index cb26762684ba80d49d43c5c785395782e77ec6c7..2e2899c867e521b006534f256466ce84c5ec7f0a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,10 @@
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
+[[package]]
+name = "bytecount"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
[[package]]
name = "cfg-if"
version = "0.1.9"
@@ -10,6 +15,7 @@ name = "first"
version = "0.1.0"
dependencies = [
"nom 5.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nom_locate 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
@@ -39,6 +45,16 @@ dependencies = [
"version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
]
+[[package]]
+name = "nom_locate"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bytecount 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nom 5.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
[[package]]
name = "rustc_version"
version = "0.2.3"
@@ -98,10 +114,12 @@ version = "1.0.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[metadata]
+"checksum bytecount 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f861d9ce359f56dbcb6e0c2a1cb84e52ad732cadb57b806adeb3c7668caccbd8"
"checksum cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "b486ce3ccf7ffd79fdeb678eac06a9e6c09fc88d33836340becb8fffe87c5e33"
"checksum lexical-core 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "b8b0f90c979adde96d19eb10eb6431ba0c441e2f9e9bdff868b2f6f5114ff519"
"checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
"checksum nom 5.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c618b63422da4401283884e6668d39f819a106ef51f5f59b81add00075da35ca"
+"checksum nom_locate 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f932834fd8e391fc7710e2ba17e8f9f8645d846b55aa63207e17e110a1e1ce35"
"checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
"checksum ryu 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c92464b447c0ee8c4fb3824ecc8383b81717b9f1e74ba2e72540aef7b9f82997"
"checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
diff --git a/examples/main_locate.rs b/examples/main_locate.rs
index 3ee29998f7abc3846049f39ceef6ed33ced71876..fdf884f5f69839630a866bb39945faf626934d2f 100644
--- a/examples/main_locate.rs
+++ b/examples/main_locate.rs
@@ -26,12 +26,14 @@ pub enum Expr<'a> {
BinOp(Span<'a>, Box<Expr<'a>>, Op, Box<Expr<'a>>),
}
+// this is the definititon of IResult
// type IResult<I, O, E = u32> = Result<(I, O), Err<I, E>>;
pub fn parse_i32(i: Span) -> IResult<Span, Expr> {
map(digit1, |digit_str: Span| {
Expr::Num(digit_str, digit_str.fragment.parse::<i32>().unwrap())
})(i)
+ // below is just an exapmle on howto generate an Error explicitly
// Err(Err::Error((i, ErrorKind::Alpha)))
}
diff --git a/examples/main_span_expr.rs b/examples/main_span_expr.rs
new file mode 100644
index 0000000000000000000000000000000000000000..139857ace9b12f370846b990b90960aeb7fd755b
--- /dev/null
+++ b/examples/main_span_expr.rs
@@ -0,0 +1,104 @@
+extern crate nom;
+
+use nom::{
+ branch::alt,
+ bytes::complete::tag,
+ character::complete::{digit1, multispace0},
+ combinator::map,
+ sequence::{preceded, tuple},
+ IResult,
+};
+
+use nom_locate::LocatedSpan;
+
+type Span<'a> = LocatedSpan<&'a str>;
+
+#[derive(Debug, PartialEq)]
+pub enum Op {
+ Add,
+ Sub,
+}
+
+type SpanOp<'a> = (Span<'a>, Op);
+
+fn parse_op(i: Span) -> IResult<Span, SpanOp> {
+ alt((
+ map(tag("+"), |s| (s, Op::Add)),
+ map(tag("-"), |s| (s, Op::Sub)),
+ ))(i)
+}
+
+#[derive(Debug, PartialEq)]
+pub enum Expr<'a> {
+ Num(i32),
+ BinOp(Box<SpanExpr<'a>>, SpanOp<'a>, Box<SpanExpr<'a>>),
+}
+
+type SpanExpr<'a> = (Span<'a>, Expr<'a>);
+
+pub fn parse_i32(i: Span) -> IResult<Span, SpanExpr> {
+ map(digit1, |digit_str: Span| {
+ (
+ digit_str,
+ Expr::Num(digit_str.fragment.parse::<i32>().unwrap()),
+ )
+ })(i)
+}
+
+fn parse_expr(i: Span) -> IResult<Span, SpanExpr> {
+ alt((
+ map(
+ tuple((parse_i32, preceded(multispace0, parse_op), parse_expr_ms)),
+ |(l, op, r)| (i, Expr::BinOp(Box::new(l), op, Box::new(r))),
+ ),
+ parse_i32,
+ ))(i)
+}
+
+fn parse_expr_ms(i: Span) -> IResult<Span, SpanExpr> {
+ preceded(multispace0, parse_expr)(i)
+}
+
+// dumps a Span into a String
+fn dump_span(s: &Span) -> String {
+ format!(
+ "[line :{:?}, col:{:?}, {:?}]",
+ s.line,
+ s.get_column(),
+ s.fragment
+ )
+}
+
+// dumps a SpanExpr into a String
+fn dump_expr(se: &SpanExpr) -> String {
+ let (s, e) = se;
+ match e {
+ Expr::Num(_) => dump_span(s),
+ Expr::BinOp(l, (sop, _), r) => {
+ format!("<{} {} {}>", dump_expr(l), dump_span(sop), dump_expr(r))
+ }
+ }
+}
+
+fn main() {
+ let (_, (s, e)) = parse_expr_ms(Span::new("\n 1+2 - \n3")).unwrap();
+ println!(
+ "span for the whole,expression: {:?}, \nline: {:?}, \ncolumn: {:?}",
+ s,
+ s.line,
+ s.get_column()
+ );
+
+ println!("raw e: {:?}", &e);
+ println!("pretty e {}", dump_expr(&(s, e)));
+}
+
+//
+// In this example, we have a `parse_expr_ms` is the "top" level parser.
+// It consumes white spaces, allowing the location information to reflect the exact
+// positions in the input file.
+//
+// The dump_expr will create a pretty printing of the expression with spans for
+// each terminal. This will be useful for later for precise type error reporting.
+//
+// The exrtra field is not used, it can be used for metadata, such as filename.