Update app.py

app.py

@@ -1,6 +1,6 @@
 import streamlit as st
 from sympy import (
-    symbols, integrate, diff, exp, log, ln, sin, cos, tan, sec, csc, cot, latex
+    symbols, integrate, diff, exp, log, ln, sin, cos, tan, sec, csc, cot, latex, SympifyError, sympify
 )
 
 # Define the Streamlit app
@@ -20,14 +20,13 @@ def main():
     # Input section
     st.header("Input the Function")
     function_input = st.text_input(
-        "Enter the integrand (e.g., x * exp(x), ln(x), x^2 * cos(x)):",
+        "Enter the integrand (e.g., x * exp(x), cos(ln(x)), x^2 * sin(x)):",
         "x * exp(x)",
     )
     u_input = st.text_input(
         "Choose 'u' (e.g., x for x * exp(x) or ln(x)):", "x"
     )
 
-    # Solve button
     if st.button("Solve"):
         try:
             # Define the variable and import common functions for eval()
@@ -36,9 +35,14 @@ def main():
                             "sin": sin, "cos": cos, "tan": tan, 
                             "sec": sec, "csc": csc, "cot": cot}
             
-            # Parse the integrand and `u`
-            integrand = eval(function_input, {"__builtins__": None}, safe_globals)
-            u = eval(u_input, {"__builtins__": None}, safe_globals)
+            # Validate and parse inputs
+            try:
+                integrand = sympify(function_input, locals=safe_globals)
+                u = sympify(u_input, locals=safe_globals)
+            except SympifyError:
+                st.error("Invalid input. Please use valid mathematical syntax (e.g., cos(ln(x))).")
+                return
+
             dv = integrand / u
 
             # Compute derivatives and integrals