From 590a0b807787a4561966e70a1b9cdffdbc8bf80c Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Sat, 27 Feb 2021 23:56:58 -0700
Subject: [PATCH] update the parser with the number of lines already read by
 the underlying stream (#836)

---
 crates/prolog_parser/src/parser.rs | 5 +++++
 src/machine/streams.rs             | 5 +++++
 src/read.rs                        | 8 +++++---
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/crates/prolog_parser/src/parser.rs b/crates/prolog_parser/src/parser.rs
index 0fa142f6..c72d6453 100644
--- a/crates/prolog_parser/src/parser.rs
+++ b/crates/prolog_parser/src/parser.rs
@@ -965,6 +965,11 @@ impl<'a, R: Read> Parser<'a, R> {
         self.lexer.eof()
     }
 
+    #[inline]
+    pub fn add_lines_read(&mut self, lines_read: usize) {
+        self.lexer.line_num += lines_read;
+    }
+
     #[inline]
     pub fn num_lines_read(&self) -> usize {
         self.lexer.line_num
diff --git a/src/machine/streams.rs b/src/machine/streams.rs
index c08a6ae5..56bb3836 100644
--- a/src/machine/streams.rs
+++ b/src/machine/streams.rs
@@ -366,6 +366,11 @@ impl Stream {
         ptr as *const u8
     }
 
+    #[inline]
+    pub(crate) fn lines_read(&mut self) -> usize {
+        self.stream_inst.0.borrow_mut().lines_read
+    }
+
     #[inline]
     pub(crate) fn add_lines_read(&mut self, incr_num_lines_read: usize) {
         self.stream_inst.0.borrow_mut().lines_read += incr_num_lines_read;
diff --git a/src/read.rs b/src/read.rs
index fa158414..5d7d85c0 100644
--- a/src/read.rs
+++ b/src/read.rs
@@ -185,7 +185,6 @@ impl MachineState {
         let mut parser = Parser::new(&mut stream, atom_tbl, self.flags);
 
         parser.devour_whitespace()?;
-        inner.add_lines_read(parser.num_lines_read());
 
         let result = parser.eof();
         let buf = stream.take_buf();
@@ -203,10 +202,13 @@ impl MachineState {
         let mut stream = parsing_stream(inner.clone())?;
 
         let (term, num_lines_read) = {
+            let prior_num_lines_read = inner.lines_read();
             let mut parser = Parser::new(&mut stream, atom_tbl, self.flags);
-            let term = parser.read_term(&CompositeOpDir::new(op_dir, None))?;
 
-            (term, parser.num_lines_read())
+            parser.add_lines_read(prior_num_lines_read);
+
+            let term = parser.read_term(&CompositeOpDir::new(op_dir, None))?;
+            (term, parser.num_lines_read() - prior_num_lines_read)
         };
 
         inner.add_lines_read(num_lines_read);
-- 
2.54.0