From 5bb556038dfbdd2878fe1907196d84c3a536da08 Mon Sep 17 00:00:00 2001
From: Lewis Van Winkle <lv@codeplea.com>
Date: Mon, 28 Nov 2016 18:20:10 -0600
Subject: [PATCH] Added support for underscore in variable names.

---
 test.c     | 4 ++--
 tinyexpr.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/test.c b/test.c
index e976d95..b86a83f 100644
--- a/test.c
+++ b/test.c
@@ -237,7 +237,7 @@ void test_nans() {
 void test_variables() {
 
     double x, y, test;
-    te_variable lookup[] = {{"x", &x}, {"y", &y}, {"test", &test}};
+    te_variable lookup[] = {{"x", &x}, {"y", &y}, {"te_st", &test}};
 
     int err;
 
@@ -253,7 +253,7 @@ void test_variables() {
     lok(expr3);
     lok(!err);
 
-    te_expr *expr4 = te_compile("test+5", lookup, 3, &err);
+    te_expr *expr4 = te_compile("te_st+5", lookup, 3, &err);
     lok(expr4);
     lok(!err);
 
diff --git a/tinyexpr.c b/tinyexpr.c
index 58717c2..6c3cb7a 100644
--- a/tinyexpr.c
+++ b/tinyexpr.c
@@ -207,7 +207,7 @@ void next_token(state *s) {
             if (s->next[0] >= 'a' && s->next[0] <= 'z') {
                 const char *start;
                 start = s->next;
-                while ((s->next[0] >= 'a' && s->next[0] <= 'z') || (s->next[0] >= '0' && s->next[0] <= '9')) s->next++;
+                while ((s->next[0] >= 'a' && s->next[0] <= 'z') || (s->next[0] >= '0' && s->next[0] <= '9') || (s->next[0] == '_')) s->next++;
 
                 const te_variable *var = find_lookup(s, start, s->next - start);
                 if (!var) var = find_builtin(start, s->next - start);