diff --git a/benches/eval.rs b/benches/eval.rs
index 8071f51..2ae8769 100644
--- a/benches/eval.rs
+++ b/benches/eval.rs
@@ -2,6 +2,8 @@
 extern crate criterion;
 extern crate loot_condition_interpreter;
 
+use std::str::FromStr;
+
 use criterion::Criterion;
 use loot_condition_interpreter::{Expression, GameType, State};
 
@@ -22,7 +24,7 @@ fn generate_plugin_versions() -> Vec<(String, String)> {
 fn criterion_benchmark(c: &mut Criterion) {
     c.bench_function("Expression.eval() file(path)", |b| {
         let state = State::new(GameType::Tes4, ".".into(), ".".into());
-        let expression = Expression::parse("file(\"Cargo.toml\")").unwrap().1;
+        let expression = Expression::from_str("file(\"Cargo.toml\")").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -31,7 +33,7 @@ fn criterion_benchmark(c: &mut Criterion) {
 
     c.bench_function("Expression.eval() file(regex)", |b| {
         let state = State::new(GameType::Tes4, ".".into(), ".".into());
-        let expression = Expression::parse("file(\"Cargo.*\")").unwrap().1;
+        let expression = Expression::from_str("file(\"Cargo.*\")").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -45,7 +47,7 @@ fn criterion_benchmark(c: &mut Criterion) {
             ".".into(),
         ).with_active_plugins(&generate_active_plugins());
 
-        let expression = Expression::parse("active(\"Blank.esm\")").unwrap().1;
+        let expression = Expression::from_str("active(\"Blank.esm\")").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -59,7 +61,7 @@ fn criterion_benchmark(c: &mut Criterion) {
             ".".into(),
         ).with_active_plugins(&generate_active_plugins());
 
-        let expression = Expression::parse("active(\"Blank.*\")").unwrap().1;
+        let expression = Expression::from_str("active(\"Blank.*\")").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -68,7 +70,7 @@ fn criterion_benchmark(c: &mut Criterion) {
 
     c.bench_function("Expression.eval() many()", |b| {
         let state = State::new(GameType::Tes4, ".".into(), ".".into());
-        let expression = Expression::parse("many(\"Cargo.*\")").unwrap().1;
+        let expression = Expression::from_str("many(\"Cargo.*\")").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -82,7 +84,7 @@ fn criterion_benchmark(c: &mut Criterion) {
             ".".into(),
         ).with_active_plugins(&generate_active_plugins());
 
-        let expression = Expression::parse("many_active(\"Blank.*\")").unwrap().1;
+        let expression = Expression::from_str("many_active(\"Blank.*\")").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -95,9 +97,7 @@ fn criterion_benchmark(c: &mut Criterion) {
             "testing-plugins/Oblivion/Data".into(),
             ".".into(),
         );
-        let expression = Expression::parse("checksum(\"Blank.esm\", 374E2A6F)")
-            .unwrap()
-            .1;
+        let expression = Expression::from_str("checksum(\"Blank.esm\", 374E2A6F)").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -111,9 +111,7 @@ fn criterion_benchmark(c: &mut Criterion) {
             ".".into(),
         ).with_plugin_versions(&generate_plugin_versions());
 
-        let expression = Expression::parse("version(\"Blank.esm\", \"5.0\", ==)")
-            .unwrap()
-            .1;
+        let expression = Expression::from_str("version(\"Blank.esm\", \"5.0\", ==)").unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
@@ -122,10 +120,9 @@ fn criterion_benchmark(c: &mut Criterion) {
 
     c.bench_function("Expression.eval() version(executable)", |b| {
         let state = State::new(GameType::Tes4, ".".into(), ".".into());
-        let expression = Expression::parse(
+        let expression = Expression::from_str(
             "version(\"loot_api-0.13.8-0-g47797cc_dev-win32/loot_api.dll\", \"0.13.8.0\", ==)",
-        ).unwrap()
-        .1;
+        ).unwrap();
 
         b.iter(|| {
             assert!(expression.eval(&state).unwrap());
diff --git a/src/lib.rs b/src/lib.rs
index 72b465b..85c2092 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -46,12 +46,6 @@ impl From<io::Error> for Error {
     }
 }
 
-impl From<pelite::resources::FindError> for Error {
-    fn from(_: pelite::resources::FindError) -> Self {
-        Error::PeParsingError
-    }
-}
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum GameType {
     Tes4,
@@ -148,17 +142,26 @@ impl Expression {
         }
         Ok(false)
     }
+}
 
-    pub fn parse(input: &str) -> IResult<&str, Expression> {
-        do_parse!(
-            input,
-            compound_conditions:
-                separated_list_complete!(ws!(tag!("or")), CompoundCondition::parse)
-                >> (Expression(compound_conditions))
-        )
+impl str::FromStr for Expression {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        parse_expression(s)
+            .map(|(_, expression)| expression)
+            .map_err(Error::from)
     }
 }
 
+fn parse_expression(input: &str) -> IResult<&str, Expression> {
+    do_parse!(
+        input,
+        compound_conditions: separated_list_complete!(ws!(tag!("or")), CompoundCondition::parse)
+            >> (Expression(compound_conditions))
+    )
+}
+
 impl fmt::Display for Expression {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let strings: Vec<String> = self.0.iter().map(CompoundCondition::to_string).collect();
@@ -223,7 +226,7 @@ impl Condition {
                     preceded!(ws!(tag!("not")), call!(Function::parse)) => {
                         |f| Condition::InvertedFunction(f)
                     } |
-                    delimited!(tag!("("), call!(Expression::parse), tag!(")")) => {
+                    delimited!(tag!("("), call!(parse_expression), tag!(")")) => {
                         |e| Condition::Expression(e)
                     }
             ) >> (condition)
@@ -247,6 +250,7 @@ mod tests {
     use super::*;
 
     use std::fs::create_dir;
+    use std::str::FromStr;
 
     fn state<T: Into<PathBuf>>(data_path: T) -> State {
         let data_path = data_path.into();
@@ -409,7 +413,7 @@ mod tests {
 
     #[test]
     fn expression_parse_should_handle_a_single_compound_condition() {
-        let result = Expression::parse("file(\"Cargo.toml\")").unwrap().1;
+        let result = Expression::from_str("file(\"Cargo.toml\")").unwrap();
 
         match result.0.as_slice() {
             [CompoundCondition(_)] => {}
@@ -419,9 +423,7 @@ mod tests {
 
     #[test]
     fn expression_parse_should_handle_multiple_compound_conditions() {
-        let result = Expression::parse("file(\"Cargo.toml\") or file(\"Cargo.toml\")")
-            .unwrap()
-            .1;
+        let result = Expression::from_str("file(\"Cargo.toml\") or file(\"Cargo.toml\")").unwrap();
 
         match result.0.as_slice() {
             [CompoundCondition(_), CompoundCondition(_)] => {}
diff --git a/src/version.rs b/src/version.rs
index b869af4..a13c2ef 100644
--- a/src/version.rs
+++ b/src/version.rs
@@ -30,7 +30,8 @@ pub struct Version {
 impl Version {
     pub fn read_file_version(file_path: &Path) -> Result<Self, Error> {
         let file_map = FileMap::open(file_path)?;
-        let version_info = get_pe_version_info(file_map.as_ref())?;
+        let version_info =
+            get_pe_version_info(file_map.as_ref()).map_err(|_| Error::PeParsingError)?;
 
         if let Some(fixed_file_info) = version_info.fixed() {
             let version = format!(