add a FromStr instance for GenericPathComponent, and a new type PathError

4 files changed, 28 insertions, 1 deletions

diff --git a/src/main.rs b/src/main.rs
index 3b7d26d..a8d8f50 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@ use std::collections::HashSet;
 use std::io;
 use std::io::prelude::*;
 use std::os::unix::fs::PermissionsExt;
+use std::str::FromStr;
 
 #[macro_use] extern crate lalrpop_util;
 
diff --git a/src/path.rs b/src/path.rs
index 2e599bf..c566b9c 100644
--- a/src/path.rs
+++ b/src/path.rs
@@ -175,6 +175,16 @@ impl std::str::FromStr for DirectoryName {
 }
 
 
+impl std::str::FromStr for GenericPathComponent {
+  type Err = PathError;
+
+  fn from_str(input: &str) -> std::result::Result<Self, Self::Err> {
+    parser::PathComponentParser::new().parse(input).map_err(
+        |e| PathError::Parse(e.to_string()))
+  }
+}
+
+
 impl AbsoluteDirectoryPath {
   pub fn to_sys_path(&self) -> std::path::PathBuf {
     let mut result = std::path::PathBuf::new();
diff --git a/src/path/error.rs b/src/path/error.rs
index 1162a3b..0ee5423 100644
--- a/src/path/error.rs
+++ b/src/path/error.rs
@@ -8,11 +8,18 @@ pub enum DirectoryNameError {
   ContainsSlash(String),
 }
 
+#[derive(Clone,Debug,Eq,Hash,Ord,PartialEq,PartialOrd)]
+pub enum PathError {
+  Parse(String),
+}
+
 
 impl std::error::Error for FileNameError { }
 
 impl std::error::Error for DirectoryNameError { }
 
+impl std::error::Error for PathError { }
+
 impl std::fmt::Display for FileNameError {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     match self {
@@ -33,3 +40,12 @@ impl std::fmt::Display for DirectoryNameError {
   }
 }
 
+impl std::fmt::Display for PathError {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    match self {
+      PathError::Parse(s) =>
+        f.write_fmt(format_args!("Syntax error in path: {}", s)),
+    }
+  }
+}
+
diff --git a/src/path/parser.lalrpop b/src/path/parser.lalrpop
index 9705fc3..c41b3fd 100644
--- a/src/path/parser.lalrpop
+++ b/src/path/parser.lalrpop
@@ -70,7 +70,7 @@ PathNoColons2: Vec<GenericPathComponent> = {
   }
 }
 
-PathComponent: GenericPathComponent = {
+pub PathComponent: GenericPathComponent = {
   DOT => GenericPathComponent::CurrentDirectory,
   DOT_DOT => GenericPathComponent::ParentDirectory,
   <PATH_COMPONENT_NO_COLONS> =>