diff options
author | Ryan Leckey <ryan@launchbadge.com> | 2017-06-13 18:55:40 -0700 |
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committer | Ryan Leckey <ryan@launchbadge.com> | 2017-06-13 18:55:40 -0700 |
commit | 47ad966e064f842056e7c1b7abe8ef64d127f5be (patch) | |
tree | 4dd4e14168383dd818fe6add8ed0a5f4900d85b6 /src/path | |
parent | 1266d110ba31a9d0f9f4908a5a30291899ffc8fc (diff) | |
parent | 312f32905f518fa59e1daf3fc8224dadf584b484 (diff) |
Merge branch 'serde'
Diffstat (limited to 'src/path')
-rw-r--r-- | src/path/mod.rs | 161 | ||||
-rw-r--r-- | src/path/parser.rs | 121 |
2 files changed, 282 insertions, 0 deletions
diff --git a/src/path/mod.rs b/src/path/mod.rs new file mode 100644 index 0000000..ff93287 --- /dev/null +++ b/src/path/mod.rs @@ -0,0 +1,161 @@ +use std::str::FromStr; +use std::collections::HashMap; +use nom::ErrorKind; +use error::*; +use value::{Value, ValueKind}; + +mod parser; + +#[derive(Debug, Eq, PartialEq, Clone, Hash)] +pub enum Expression { + Identifier(String), + Child(Box<Expression>, String), + Subscript(Box<Expression>, i32), +} + +impl FromStr for Expression { + type Err = ConfigError; + + fn from_str(s: &str) -> Result<Expression> { + parser::from_str(s).map_err(ConfigError::PathParse) + } +} + +impl Expression { + pub fn get(self, root: &Value) -> Option<&Value> { + match self { + Expression::Identifier(id) => { + match root.kind { + // `x` access on a table is equivalent to: map[x] + ValueKind::Table(ref map) => map.get(&id), + + // all other variants return None + _ => None, + } + } + + Expression::Child(expr, key) => { + match expr.get(root) { + Some(value) => { + match value.kind { + // Access on a table is identical to Identifier, it just forwards + ValueKind::Table(ref map) => map.get(&key), + + // all other variants return None + _ => None, + } + } + + _ => None, + } + } + + _ => { + unimplemented!(); + } + } + } + + pub fn get_mut<'a>(&self, root: &'a mut Value) -> Option<&'a mut Value> { + match *self { + Expression::Identifier(ref id) => { + match root.kind { + ValueKind::Table(ref mut map) => { + Some(map.entry(id.clone()).or_insert_with(|| Value::new(None, ValueKind::Nil))) + } + + _ => None, + } + } + + Expression::Child(ref expr, ref key) => { + match expr.get_mut(root) { + Some(value) => { + match value.kind { + ValueKind::Table(ref mut map) => { + Some(map.entry(key.clone()).or_insert_with(|| Value::new(None, ValueKind::Nil))) + } + + _ => { + *value = HashMap::<String, Value>::new().into(); + + if let ValueKind::Table(ref mut map) = value.kind { + Some(map.entry(key.clone()).or_insert_with(|| Value::new(None, ValueKind::Nil))) + } else { + println!("WHAT THE FUCK?"); + + unreachable!(); + } + } + } + } + + _ => None, + } + } + + _ => { + unimplemented!(); + } + } + } + + pub fn set<'a>(&self, root: &'a mut Value, value: Value) { + match *self { + Expression::Identifier(ref id) => { + // Ensure that root is a table + match root.kind { + ValueKind::Table(_) => { } + + _ => { + *root = HashMap::<String, Value>::new().into(); + } + } + + match value.kind { + ValueKind::Table(ref incoming_map) => { + // Pull out another table + let mut target = if let ValueKind::Table(ref mut map) = root.kind { + map.entry(id.clone()).or_insert_with(|| HashMap::<String, Value>::new().into()) + } else { + unreachable!(); + }; + + // Continue the deep merge + for (key, val) in incoming_map { + Expression::Identifier(key.clone()).set(&mut target, val.clone()); + } + } + + _ => { + if let ValueKind::Table(ref mut map) = root.kind { + // Just do a simple set + map.insert(id.clone(), value); + } + } + } + } + + Expression::Child(ref expr, ref key) => { + if let Some(parent) = expr.get_mut(root) { + match parent.kind { + ValueKind::Table(_) => { + Expression::Identifier(key.clone()).set(parent, value); + } + + _ => { + // Didn't find a table. Oh well. Make a table and do this anyway + *parent = HashMap::<String, Value>::new().into(); + + Expression::Identifier(key.clone()).set(parent, value); + } + } + } + } + + _ => { + unimplemented!(); + } + } + } +} diff --git a/src/path/parser.rs b/src/path/parser.rs new file mode 100644 index 0000000..ee3fb65 --- /dev/null +++ b/src/path/parser.rs @@ -0,0 +1,121 @@ +use nom::*; +use std::str::{FromStr, from_utf8}; +use super::Expression; + +named!(ident_<String>, + map!( + map_res!(is_a!( + "abcdefghijklmnopqrstuvwxyz \ + ABCDEFGHIJKLMNOPQRSTUVWXYZ \ + 0123456789 \ + _-" + ), from_utf8), + |s: &str| { + s.to_string() + } + ) +); + +named!(integer <i32>, + map_res!( + map_res!( + ws!(digit), + from_utf8 + ), + FromStr::from_str + ) +); + +named!(ident<Expression>, map!(ident_, Expression::Identifier)); + +#[allow(cyclomatic_complexity)] +fn postfix(expr: Expression) -> Box<Fn(&[u8]) -> IResult<&[u8], Expression>> { + Box::new(move |i: &[u8]| { + alt!(i, + do_parse!( + tag!(".") >> + id: ident_ >> + (Expression::Child(Box::new(expr.clone()), id)) + ) | + delimited!( + char!('['), + do_parse!( + negative: opt!(tag!("-")) >> + num: integer >> + (Expression::Subscript( + Box::new(expr.clone()), + num * (if negative.is_none() { 1 } else { -1 }) + )) + ), + char!(']') + ) + ) + }) +} + +pub fn from_str(input: &str) -> Result<Expression, ErrorKind> { + match ident(input.as_bytes()) { + IResult::Done(mut rem, mut expr) => { + while !rem.is_empty() { + match postfix(expr)(rem) { + IResult::Done(rem_, expr_) => { + rem = rem_; + expr = expr_; + } + + // Forward Incomplete and Error + result => { + return result.to_result(); + } + } + } + + Ok(expr) + } + + // Forward Incomplete and Error + result => result.to_result(), + } +} + +#[cfg(test)] +mod test { + use super::*; + use super::Expression::*; + + #[test] + fn test_id() { + let parsed: Expression = from_str("abcd").unwrap(); + assert_eq!(parsed, Identifier("abcd".into())); + } + + #[test] + fn test_id_dash() { + let parsed: Expression = from_str("abcd-efgh").unwrap(); + assert_eq!(parsed, Identifier("abcd-efgh".into())); + } + + #[test] + fn test_child() { + let parsed: Expression = from_str("abcd.efgh").unwrap(); + let expected = Child(Box::new(Identifier("abcd".into())), "efgh".into()); + + assert_eq!(parsed, expected); + } + + #[test] + fn test_subscript() { + let parsed: Expression = from_str("abcd[12]").unwrap(); + let expected = Subscript(Box::new(Identifier("abcd".into())), 12); + + assert_eq!(parsed, expected); + } + + #[test] + fn test_subscript_neg() { + let parsed: Expression = from_str("abcd[-1]").unwrap(); + let expected = Subscript(Box::new(Identifier("abcd".into())), -1); + + assert_eq!(parsed, expected); + } +} |