Simplify

src/core/builtins/parameter.rs

@@ -33,7 +33,10 @@ fn set_local(arg: &str, core: &mut ShellCore, layer: usize) -> Result<(), ExecEr
         return core.db.set_param(&name, "", Some(layer));
     }
 
-    Substitution::parse(&mut feeder, core)?.unwrap().eval(core, Some(layer), false)
+    match Substitution::parse(&mut feeder, core) {
+        Ok(ans) => ans.unwrap().eval(core, Some(layer), false),
+        Err(e) => Err(ExecError::ParseError(e)),
+    }
 }
 
 fn set_local_array(arg: &str, core: &mut ShellCore, layer: usize) -> Result<(), ExecError> {

src/error/exec.rs

@@ -2,6 +2,7 @@
 //SPDX-License-Identifier: BSD-3-Clause
 
 use crate::ShellCore;
+use crate::error::parse::ParseError;
 
 #[derive(Debug)]
 pub enum ExecError {
@@ -18,6 +19,7 @@ pub enum ExecError {
     VariableReadOnly(String),
     VariableInvalid(String),
     OperandExpected(String),
+    ParseError(ParseError),
     Recursion(String),
     SubstringMinus(i64),
     Other(String),
@@ -39,6 +41,7 @@ impl From<ExecError> for String {
             ExecError::VariableReadOnly(name) => format!("{}: readonly variable", name),
             ExecError::VariableInvalid(name) => format!("`{}': not a valid identifier", name),
             ExecError::OperandExpected(token) => format!("{0}: syntax error: operand expected (error token is \"{0}\")", token),
+            ExecError::ParseError(p) => From::from(p),
             ExecError::Recursion(token) => format!("{0}: expression recursion level exceeded (error token is \"{0}\")", token), 
             ExecError::SubstringMinus(n) => format!("{}: substring expression < 0", n),
             ExecError::Other(name) => name,

src/error/parse.rs

@@ -1,21 +1,19 @@
 //SPDX-FileCopyrightText: 2024 Ryuichi Ueda [email protected]
 //SPDX-License-Identifier: BSD-3-Clause
 
-use super::exec::ExecError;
-
 #[derive(Debug)]
 pub enum ParseError {
     UnexpectedSymbol(String),
     UnexpectedEof,
     Interrupted,
 }
 
-impl From<ParseError> for ExecError {
-    fn from(e: ParseError) -> ExecError {
+impl From<ParseError> for String {
+    fn from(e: ParseError) -> String {
         match e {
-            ParseError::UnexpectedSymbol(s) => ExecError::Other(s),
-            ParseError::UnexpectedEof => ExecError::Other("eof".to_string()),
-            ParseError::Interrupted => ExecError::Other("Interrupted".to_string()),
+            ParseError::UnexpectedSymbol(s) => format!("Unexpected token: {}", s),
+            ParseError::UnexpectedEof => "syntax error: unexpected end of file".to_string(),
+            ParseError::Interrupted => "interrupted".to_string(),
         }
     }
 }