From c84dc83799cec33b71126e624cd914125d8d2a43 Mon Sep 17 00:00:00 2001
From: Alexei Sheplyakov <alexei.sheplyakov@gmail.com>
Date: Mon, 5 Jul 2010 09:15:20 +0200
Subject: [PATCH] Parser: handle abbreviations as advertized in the manual.

The following example from the tutorial

GiNaC::symbol x, y;
GiNaC::symtab table;
table["x"] = x+log(y)+1;
GiNaC::parser reader(table);
GiNaC::ex e = reader("5*x3 - x2");

fails with the following exception:

terminate called after throwing an instance of 'std::invalid_argument'
what(): find_or_insert_symbol: name "x" does not correspond to a symbol

Remove silly checks from find_or_insert_symbol, and fix its return value
(should be ex, not symbol).
---
 ginac/parser/parse_context.cpp | 13 +++----------
 ginac/parser/parse_context.h   |  4 ++--
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/ginac/parser/parse_context.cpp b/ginac/parser/parse_context.cpp
index 7a7867a0..2230d614 100644
--- a/ginac/parser/parse_context.cpp
+++ b/ginac/parser/parse_context.cpp
@@ -27,19 +27,12 @@
 
 namespace GiNaC {
 
-symbol
+ex
 find_or_insert_symbol(const std::string& name, symtab& syms, const bool strict)
 {
 	symtab::const_iterator p = syms.find(name);
-	if (p != syms.end()) {
-		if (is_a<symbol>(p->second))
-			return ex_to<symbol>(p->second);
-		else
-			throw std::invalid_argument(
-				std::string("find_or_insert_symbol: name \"")
-				+ name + "\" does not correspond to a symbol");
-	}
-
+	if (p != syms.end())
+		return p->second;
 
 	if (strict)
 		throw std::invalid_argument(
diff --git a/ginac/parser/parse_context.h b/ginac/parser/parse_context.h
index fe52700d..1145a871 100644
--- a/ginac/parser/parse_context.h
+++ b/ginac/parser/parse_context.h
@@ -41,12 +41,12 @@ namespace GiNaC {
 typedef std::map<std::string, ex> symtab;
 
 /**
- * Find the symbol with the @a name in the symbol table @a syms.
+ * Find the symbol (or abbreviation) with the @a name in the symbol table @a syms.
  *
  * If symbol is missing and @a strict = false, insert it, otherwise
  * throw an exception.
  */
-extern symbol
+extern ex 
 find_or_insert_symbol(const std::string& name, symtab& syms,
 	              const bool strict);
 
-- 
2.44.0