From 07daff9331dbdc607584edbf1a8fb3e415c338ea Mon Sep 17 00:00:00 2001
From: Jonas Maier <>
Date: Fri, 22 May 2026 17:44:24 +0200
Subject: lenient block parsing for completion

---
 src/parse/mod.rs | 85 ++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 52 insertions(+), 33 deletions(-)

(limited to 'src/parse/mod.rs')

diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index ffbdfe5..102b334 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -403,13 +403,8 @@ pub struct FunDecl<S: Stage> {
 impl Parse for Block {
     fn parse(b: &mut Cursor<'_>) -> Result<Self> {
         let mut commands = Vec::new();
-        b.spaces();
 
-        if b.has() && b.peek() == b'{' {
-            b.adv();
-        } else {
-            return Err(ParseError::NotABlock);
-        }
+        b.consume_keyword(Keyword::OpenBrace)?;
 
         loop {
             while {
@@ -419,7 +414,7 @@ impl Parse for Block {
                 b.adv();
             }
 
-            if b.has() && b"})".contains(&b.peek()) {
+            if b.has() && b"})".contains(&b.peek()) || b.is_completion() && b.is_empty() {
                 break;
             }
 
@@ -427,16 +422,10 @@ impl Parse for Block {
             commands.push(cmd);
         }
 
-        let finished_parsing = if b.has() {
-            if b.peek() != b'}' {
-                return Err(ParseError::Expected('}'));
-            }
-            b.adv();
-            true
-        } else if !b.is_completion() {
-            return Err(ParseError::Expected('}'));
-        } else {
-            false
+        let finished_parsing = match b.consume_keyword(Keyword::CloseBrace) {
+            Ok(_) => true,
+            Err(_) if b.is_completion() => false,
+            Err(e) => Err(e)?,
         };
 
         Ok(Self {
@@ -1290,7 +1279,8 @@ pub trait Parse: Sized {
     }
 }
 
-enum ParseMode {
+#[derive(Copy, Clone)]
+pub enum ParseMode {
     Command,
     Completion,
 }
@@ -1302,7 +1292,7 @@ pub struct Cursor<'a> {
     /// if the last byte that was consumed was whitespace or part of a word
     spaced: bool,
 
-    backtrace: bool,
+    pub backtrace: bool,
 }
 
 #[derive(Default)]
@@ -1314,7 +1304,7 @@ struct SpaceStats {
 }
 
 impl<'a> Cursor<'a> {
-    fn new(buf: &'a [u8], mode: ParseMode) -> Self {
+    pub fn new(buf: &'a [u8], mode: ParseMode) -> Self {
         Self {
             buf,
             mode,
@@ -1323,6 +1313,10 @@ impl<'a> Cursor<'a> {
         }
     }
 
+    pub fn remaining(&self) -> &[u8] {
+        self.buf
+    }
+
     // non empty
     fn has(&self) -> bool {
         !self.buf.is_empty()
@@ -1336,8 +1330,12 @@ impl<'a> Cursor<'a> {
         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) {
+            if self.buf.is_empty() {
+                println!("{word} <EOF>\r");
+            } else {
+                println!("{word} {}\r", self.buf[0] as char);
+            }
+            for l in bt.lines().skip(4).take(8) {
                 println!("{l}\r");
             }
             println!("\r");
@@ -1413,20 +1411,30 @@ impl<'a> Cursor<'a> {
     }
 
     fn consume_keyword(&mut self, kw: Keyword) -> Result<()> {
-        self.spaces();
         let bytes = kw.as_bytes();
+
+        if self.backtrace {
+            self.bt(&format!("keyword {kw:?}"));
+        }
+
+        self.spaces();
         if self.buf.starts_with(bytes) {
-            if kw.requires_space() && self.buf.len() > bytes.len() {
-                if self.buf[bytes.len()].is_ascii_whitespace() {
+            if kw.requires_space() {
+                if self.buf.len() > bytes.len() && self.buf[bytes.len()].is_ascii_whitespace() {
                     self.buf = &self.buf[bytes.len() + 1..];
                     self.spaces();
                     Ok(())
                 } else {
-                    self.buf = &self.buf[bytes.len()..];
-                    self.spaces();
-                    Err(ParseError::ExpectedKeyword(kw))
+                    if self.is_completion() {
+                        self.buf = &self.buf[bytes.len()..];
+                        Ok(())
+                    } else {
+                        Err(ParseError::ExpectedKeyword(kw))
+                    }
                 }
             } else {
+                self.buf = &self.buf[bytes.len()..];
+                self.spaces();
                 Ok(())
             }
         } else {
@@ -1441,6 +1449,8 @@ pub enum Keyword {
     While,
     Else,
     Elif,
+    OpenBrace,
+    CloseBrace,
 }
 
 impl Keyword {
@@ -1450,6 +1460,8 @@ impl Keyword {
             Keyword::While => b"while",
             Keyword::Elif => b"elif",
             Keyword::Else => b"else",
+            Keyword::OpenBrace => b"{",
+            Keyword::CloseBrace => b"}",
         }
     }
 
@@ -1459,13 +1471,15 @@ impl Keyword {
             Keyword::While => true,
             Keyword::Elif => true,
             Keyword::Else => false,
+            Keyword::OpenBrace => false,
+            Keyword::CloseBrace => false,
         }
     }
 }
 
-impl Parse for If<PreExpansion> {
-    fn parse(b: &mut Cursor<'_>) -> Result<Self> {
-        b.consume_keyword(Keyword::If)?;
+impl If<PreExpansion> {
+    fn parse_internal(b: &mut Cursor<'_>, first_keyword: Keyword) -> Result<Self> {
+        b.consume_keyword(first_keyword)?;
 
         let mut res = If {
             condition: Pipes::parse(b)?,
@@ -1493,8 +1507,7 @@ impl Parse for If<PreExpansion> {
 
         res.false_block = if b.consume_keyword(Keyword::Else).is_ok() {
             Block::parse(b)?
-        } else if b.consume_keyword(Keyword::Elif).is_ok() {
-            let elif = If::parse(b)?;
+        } else if let Ok(elif) = Self::parse_internal(b, Keyword::Elif) {
             Block {
                 finished_parsing: elif.parse_progress.is_done(),
                 commands: vec![Ast::If(elif)],
@@ -1512,6 +1525,12 @@ impl Parse for If<PreExpansion> {
     }
 }
 
+impl Parse for If<PreExpansion> {
+    fn parse(b: &mut Cursor<'_>) -> Result<Self> {
+        Self::parse_internal(b, Keyword::If)
+    }
+}
+
 impl Parse for While {
     fn parse(b: &mut Cursor<'_>) -> Result<Self> {
         b.spaces();
-- 
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