Correctly report the line context when there is a valexpr parsing error.

src/error.h

@@ -63,15 +63,29 @@ inline string file_context(const path& file, std::size_t line) {
   return buf.str();
 }
 
-inline string line_context(const string& line, istream_pos_type pos) {
+inline string line_context(const string&    line,
+			   istream_pos_type pos     = istream_pos_type(0),
+			   istream_pos_type end_pos = istream_pos_type(0))
+{
   std::ostringstream buf;
-  buf << "  " << line << "  ";
-  istream_pos_type idx = (pos == istream_pos_type(0) ?
-			  istream_pos_type(line.length()) : pos);
-  idx -= 1;
-  for (istream_pos_type i = 0; i < idx; i += 1)
-    buf << " ";
-  buf << "^" << std::endl;
+  buf << "  " << line << "\n";
+
+  if (pos != istream_pos_type(0)) {
+    buf << "  ";
+    if (end_pos == istream_pos_type(0)) {
+      for (istream_pos_type i = 0; i < pos; i += 1)
+	buf << " ";
+      buf << "^\n";
+    } else {
+      for (istream_pos_type i = 0; i < end_pos; i += 1) {
+	if (i >= pos)
+	  buf << "^";
+	else
+	  buf << " ";
+      }
+      buf << '\n';
+    }
+  }
   return buf.str();
 }
 

src/parser.cc

@@ -399,11 +399,21 @@ expr_t::parser_t::parse(std::istream& in, const flags_t flags,
     return top_node;
   }
   catch (const std::exception& err) {
-    add_error_context("While parsing value expression:");
     if (original_string) {
-      istream_pos_type pos = in.tellg();
-      pos -= 1;
-      add_error_context(line_context(*original_string, pos));
+      add_error_context("While parsing value expression:");
+
+      istream_pos_type end_pos = in.tellg();
+      istream_pos_type pos     = end_pos;
+
+      pos -= lookahead.length;
+
+      DEBUG("parser.error", "original_string = '" << *original_string << "'");
+      DEBUG("parser.error", "            pos = " << pos);
+      DEBUG("parser.error", "        end_pos = " << end_pos);
+      DEBUG("parser.error", "     token kind = " << int(lookahead.kind));
+      DEBUG("parser.error", "   token length = " << lookahead.length);
+
+      add_error_context(line_context(*original_string, pos, end_pos));
     }
     throw;
   }

src/token.cc

@@ -347,24 +347,32 @@ void expr_t::token_t::next(std::istream& in, const uint_least8_t pflags)
     if (pflags & EXPR_PARSE_NO_REDUCE)
       parse_flags |= AMOUNT_PARSE_NO_REDUCE;
 
-    amount_t temp;
-    if (! temp.parse(in, parse_flags | AMOUNT_PARSE_SOFT_FAIL)) {
-      // If the amount had no commodity, it must be an unambiguous
-      // variable reference
+    try {
+      amount_t temp;
+      if (! temp.parse(in, parse_flags | AMOUNT_PARSE_SOFT_FAIL)) {
+	// If the amount had no commodity, it must be an unambiguous
+	// variable reference
 
-      in.clear();
-      in.seekg(pos, std::ios::beg);
-      if (in.fail())
-	throw_(parse_error, "Failed to reset input stream");
+	in.clear();
+	in.seekg(pos, std::ios::beg);
+	if (in.fail())
+	  throw_(parse_error, "Failed to reset input stream");
 
-      c = in.peek();
-      if (std::isdigit(c) || c == '.')
-	expected('\0', c);
+	c = in.peek();
+	if (std::isdigit(c) || c == '.')
+	  expected('\0', c);
 
-      parse_ident(in);
-    } else {
-      kind = VALUE;
-      value = temp;
+	parse_ident(in);
+      } else {
+	kind   = VALUE;
+	value  = temp;
+	length = in.tellg() - pos;
+      }
+    }
+    catch (const std::exception& err) {
+      kind   = ERROR;
+      length = in.tellg() - pos;
+      throw;
     }
     break;
   }
@@ -381,7 +389,11 @@ void expr_t::token_t::rewind(std::istream& in)
 
 void expr_t::token_t::unexpected()
 {
-  switch (kind) {
+  kind_t prev_kind = kind;
+
+  kind = ERROR;
+
+  switch (prev_kind) {
   case TOK_EOF:
     throw_(parse_error, "Unexpected end of expression");
   case IDENT:
@@ -395,17 +407,19 @@ void expr_t::token_t::unexpected()
 
 void expr_t::token_t::expected(char wanted, char c)
 {
-  if (c == '\0') {
-    if (wanted)
-      throw_(parse_error, "Missing '" << wanted << "'");
-    else
+  kind = ERROR;
+
+  if (c == '\0' || c == -1) {
+    if (wanted == '\0' || wanted == -1)
       throw_(parse_error, "Unexpected end");
+    else
+      throw_(parse_error, "Missing '" << wanted << "'");
   } else {
-    if (wanted)
+    if (wanted == '\0' || wanted == -1)
+      throw_(parse_error, "Invalid char '" << c << "'");
+    else
       throw_(parse_error, "Invalid char '" << c
 	     << "' (wanted '" << wanted << "')");
-    else
-      throw_(parse_error, "Invalid char '" << c << "'");
   }
 }
 

src/token.h

@@ -39,6 +39,7 @@ namespace ledger {
 struct expr_t::token_t : public noncopyable
 {
   enum kind_t {
+    ERROR,			// an error occurred while tokenizing
     VALUE,			// any kind of literal value
     IDENT,			// [A-Za-z_][-A-Za-z0-9_:]*
     MASK,			// /regexp/
@@ -109,8 +110,7 @@ struct expr_t::token_t : public noncopyable
   void next(std::istream& in, const uint_least8_t flags);
   void rewind(std::istream& in);
   void unexpected();
-
-  static void expected(char wanted, char c = '\0');
+  void expected(char wanted, char c = '\0');
 };
 
 } // namespace ledger