From 2e55d27f565ec96c7238b35191ae5c65c2b6bc57 Mon Sep 17 00:00:00 2001
From: Jonas Maier <>
Date: Fri, 6 Mar 2026 18:49:33 +0100
Subject: shell expansion somewhat working (?)

---
 src/parse.rs | 132 ++++++++++++++++++++++++++++-------------------------------
 1 file changed, 63 insertions(+), 69 deletions(-)

(limited to 'src/parse.rs')

diff --git a/src/parse.rs b/src/parse.rs
index 2ed0dbf..b2433a8 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -106,7 +106,7 @@ impl ExpString {
 
 fn is_symbol(x: u8) -> bool {
     match x {
-        b'|' | b'{' | b'}' | b'$' => true,
+        b'|' | b'{' | b'}' | b'$' | b'(' | b')' | b'\'' | b'"' => true,
         _ => false,
     }
 }
@@ -152,14 +152,16 @@ impl Parse for ExpString {
     fn parse(b: &mut Cursor<'_>) -> Result<Self> {
         b.spaces();
         if b.is_empty() {
-            return Err(ParseError::Eof);
+            return Err(ParseError::NotAString);
         }
 
         let mut delim = b.peek();
-        if delim != b'\'' && delim != b'"' {
-            delim = b' ';
-        } else {
+        if delim == b'\'' || delim == b'"' {
             b.adv();
+        } else if is_symbol(delim) && delim != b'$' {
+            return Err(ParseError::NotAString);
+        } else {
+            delim = b' ';
         }
 
         let mut parts = Vec::new();
@@ -181,13 +183,17 @@ impl Parse for ExpString {
                 continue;
             }
 
-            if x == delim {
+            if x == delim || (b.peek_space() && delim == b' ') {
                 if delim != b' ' {
                     b.adv();
                 }
                 return Ok(Self { parts });
             }
 
+            if delim == b' ' && is_symbol(x) && x != b'$' {
+                return Ok(Self { parts });
+            }
+
             b.adv();
 
             if delim == b'\'' {
@@ -231,7 +237,16 @@ impl Parse for ExpString {
                     b.adv();
                     p.push(StringPart::Var(v));
                 } else if x == b'(' {
-                    todo!()
+                    b.adv();
+                    let cmd = Ast::parse(b)?;
+                    b.spaces();
+                    if b.is_empty() {
+                        return Err(ParseError::Eof);
+                    } else if b.peek() == b')' {
+                        p.push(StringPart::Cmd(cmd));
+                    } else {
+                        return Err(ParseError::Expected(')'));
+                    }
                 } else {
                     // doesn't seem to be a variable or expansion, just add $ back into the string
                     add_char(p, b'$');
@@ -241,10 +256,6 @@ impl Parse for ExpString {
                 continue;
             }
 
-            if delim == b' ' && is_symbol(x) {
-                return Ok(Self { parts });
-            }
-
             add_char(p, x);
         }
 
@@ -286,12 +297,20 @@ pub enum ParseError {
     ExpectedAlphabetic,
 
     Unknown(u8),
+
+    Expected(char),
+
+    NotAString,
 }
 
 type Result<T> = std::result::Result<T, ParseError>;
 
-pub fn do_parse(x: &[u8]) -> Result<Ast<PreExpansion>> {
-    Ast::parse(&mut Cursor::new(x, ParseMode::Command))
+pub fn do_parse(x: &[u8]) -> Res<Ast<PreExpansion>, (ParseError, &[u8])> {
+    let mut c = Cursor::new(x, ParseMode::Command);
+    match Ast::parse(&mut c) {
+        Ok(ast) => Ok(ast),
+        Err(e) => Err((e, c.buf)),
+    }
 }
 
 pub enum CompletionKind {
@@ -359,6 +378,8 @@ struct Cursor<'a> {
 
     /// if the last byte that was consumed was whitespace or part of a word
     spaced: bool,
+
+    backtrace: bool,
 }
 
 impl<'a> Cursor<'a> {
@@ -367,6 +388,7 @@ impl<'a> Cursor<'a> {
             buf,
             mode,
             spaced: false,
+            backtrace: false,
         }
     }
 
@@ -379,19 +401,40 @@ impl<'a> Cursor<'a> {
         self.buf.is_empty()
     }
 
+    fn bt(&self, word: &str) {
+        if self.backtrace {
+            let bt = std::backtrace::Backtrace::capture();
+            let bt = format!("{bt}");
+            println!("{word} {}\r", self.buf[0] as char);
+            for l in bt.lines().skip(4).take(2) {
+                println!("{l}\r");
+            }
+            println!("\r");
+        }
+    }
+
     fn peek(&self) -> u8 {
+        self.bt("peek");
         self.buf[0]
     }
 
     fn adv(&mut self) -> u8 {
+        self.bt("adv");
         let out = self.buf[0];
         self.buf = &self.buf[1..];
         self.spaced = false;
         out
     }
 
+    fn peek_space(&self) -> bool {
+        if self.buf.is_empty() {
+            return false;
+        }
+        matches!(self.buf[0], b' ' | b'\t' | b'\n' | b'\r')
+    }
+
     fn spaces(&mut self) {
-        while let Some(b' ' | b'\t') = self.buf.first() {
+        while self.peek_space() {
             self.adv();
             self.spaced = true;
         }
@@ -409,57 +452,6 @@ impl<'a> Cursor<'a> {
     }
 }
 
-fn parse_quoted_string(b: &mut Cursor<'_>, delim: u8) -> Result<Vec<u8>> {
-    // TODO: escape sequence stuff
-
-    let mut s = Vec::new();
-    while b.has() {
-        if delim == b' ' && b.peek() == b'|' {
-            return if s.len() == 0 {
-                Err(ParseError::UnexpectedPipe)
-            } else {
-                Ok(s)
-            };
-        }
-
-        if b.peek() == delim {
-            b.adv();
-            if delim == b' ' {
-                b.spaced = true;
-            }
-            return Ok(s);
-        }
-
-        s.push(b.adv());
-    }
-
-    if delim == b' ' || b.is_completion() {
-        Ok(s)
-    } else {
-        Err(ParseError::Incomplete)
-    }
-}
-
-impl Parse for Vec<u8> {
-    fn parse(b: &mut Cursor<'_>) -> Result<Self> {
-        b.spaces();
-        if b.is_empty() {
-            return Err(ParseError::Eof);
-        }
-        let c = b.peek();
-        if c == b'|' {
-            Err(ParseError::UnexpectedPipe)
-        } else if c == b'\'' || c == b'"' {
-            b.adv();
-            parse_quoted_string(b, c)
-        } else if c.is_ascii_graphic() {
-            parse_quoted_string(b, b' ')
-        } else {
-            Err(ParseError::Unknown(c))
-        }
-    }
-}
-
 impl Parse for Ast<PreExpansion> {
     fn parse(b: &mut Cursor<'_>) -> Result<Self> {
         Ok(Self::Pipes(b.parse()?))
@@ -471,14 +463,14 @@ impl Parse for Command<PreExpansion> {
         let path: ExpString = b.parse()?;
         let mut args = Vec::new();
         loop {
-            let arg: Result<ExpString> = b.parse();
-            match arg {
+            match ExpString::parse(b) {
                 Ok(arg) => args.push(arg),
-                Err(ParseError::Eof | ParseError::UnexpectedPipe) => break,
+                Err(ParseError::NotAString) => break,
                 Err(e) => Err(e)?,
             }
         }
-        Ok(Self { cmd: path, args })
+        let x = Ok(Self { cmd: path, args });
+        x
     }
 }
 
@@ -496,6 +488,8 @@ impl Parse for Pipes<PreExpansion> {
             if c == b'|' {
                 b.adv();
                 cmds.push(b.parse()?);
+            } else if is_symbol(c) {
+                return Ok(Pipes { cmds });
             } else {
                 Err(ParseError::Unknown(c))?;
             }
-- 
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