Step 1: Choose Variables and Operations

1. Open the Setup Panel on the right side of the interface.

   • This panel is used to build a regular expression by selecting variables and operations.

2. Select Variables

   • Under “1. Choose Variables”, click one or more variable buttons (e.g., a, b).
   • Selected variables will be highlighted.
   • Example: Click a and b to choose both.

   

3. Choose an Operation

   • After selecting variables, the operation buttons under “2. Choose Operation” become active.
   • Choose one operation to combine the variables:
     • Union (|): OR of variables
     • Concatenation (.): joining variables
     • Kleene Star (*): zero or more repetitions
   • Example: Click Union (|) to create a|b.

   

4. View the Current Expression

   • The Current RE field shows the constructed expression (e.g., a|b).
   • Click Convert to generate an NFA.

💡 Tip: Start with simple expressions (a, b, a|b) before trying complex ones.

Step 2: Build the NFA in the Construction Panel

1. Open the Construction Panel below the setup area.

   • This panel is used to create NFAs step by step.

2. Add States and Operations

   • Click Add a or Add b to create single-state NFAs for variables.
   • Use operations (e.g., Add union) to combine them.
   • The NFA diagram updates to show states, transitions, and ε-transitions.
   • The left panel displays details of states and transitions.

Step 3: View Operation Details

1. Highlight States and Operations

   • After performing an operation, select the states involved.
   • The diagram highlights the applied operation (e.g., “Union operation applied”).

2. Check Operation Details

   • The Operations panel on the left shows:
     • Initial and final states
     • Transitions (with ε-transitions)
     • Notes explaining construction steps

3. Understand the Process

   • Follow these details to learn Thompson’s construction step by step.

Step 4: Use Advanced Examples

1. Open Advanced Examples

   • In the Setup panel, click Show Advanced Examples.
   • Presets such as (a|b)c, (a|b)*, (ab)*, (a|b)*abb appear.

2. Select an Example

   • Click a preset. The Current RE field updates to the chosen expression.

3. Convert the Example

   • Click Convert to generate its NFA.
   • The diagram and Operations panel display construction details.

4. Explore or Reset

   • Inspect states, transitions, and ε-links.
   • Use Clear Selection to reset, or choose another example.
   • Hide examples by clicking Hide Advanced Examples.

💡 Tip: Advanced Examples help visualize complete constructions. Compare them with your manual build from earlier steps.