> ## Documentation Index
> Fetch the complete documentation index at: https://docs.julep.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# New Syntax (Important)

> Learn about the new workflow syntax and how to migrate your existing workflows

## Overview

We've updated our workflow syntax to make data flow more explicit and consistent.
These changes improve readability and make workflows more maintainable.
While this update requires modifications to existing workflows, it provides a more robust foundation for workflow development.

## 1. Input/Output Data References

The most significant change is how we reference input and output data between workflow steps. The new syntax makes the data flow more explicit by using the `steps` keyword.

### Old Syntax:

* `inputs[x]` - Referenced input data from step x
* `outputs[x]` - Referenced output data from step x
* `_x` - Shorthand for input data from step x

### New Syntax:

* `steps[x].input` - References input data from step x
* `steps[x].output` - References output data from step x
* `_x` -  Has been removed

### Example

#### Old Syntax

```yaml theme={"dark"}
- evaluate:
    input_data: inputs[0].a
    output_data: outputs[0].b
    shorthand: _0.c
```

#### New Syntax

```yaml theme={"dark"}
- evaluate:
    input: $ steps[0].input.a
    output: $ steps[0].output.b
    shorthand: $ steps[0].input.c
```

<Note>
  Notice the addition of the `$` prefix in the new syntax. This indicates that the value should be treated as a Python expression. We'll cover this in detail in the next section.
</Note>

### Key Changes:

* `inputs[0]` becomes `steps[0].input`
* `outputs[0]` becomes `steps[0].output`
* `_0` becomes `steps[0].input`
* Added `$` prefix to indicate Python expressions

## 2. Template Syntax Changes Inside `prompt` Steps

Another significant change is the removal of Jinja templates (`{{ }}`) in `log` steps and `prompt` steps. Instead, we now use Python f-strings with the `$` prefix for dynamic content.

### Old Syntax (Using Jinja):

```yaml theme={"dark"}
- prompt:
    - role: user
      content: Write me an article about the topic: {{inputs[0].topic}}
```

### New Syntax (Using f-strings):

```yaml theme={"dark"}
- prompt:
    - role: user
      content: $ f"Write me an article about the topic: {steps[0].input.topic}"
    - role: user
      content: this is only text, no need for dollar sign prefix
```

For multiple lines, you can use a multiline f-string:

```yaml theme={"dark"}
- prompt:
    - role: user
      content: |-
        $ f"""
        Write me an article about the topic: {steps[0].input.topic}.
        The article should be {steps[0].input.article_length} words long.
        """
```

<Note>
  The `$` prefix is only needed when the value contains a Python expression or f-string. Plain text content doesn't require the prefix.
</Note>

## 3. When to Use the \$ Prefix

The `$` prefix should be used in two scenarios:

1. When referencing step data (inputs/outputs)
2. When using Python expressions or f-strings

#### Examples:

```yaml theme={"dark"}
steps:
  - prompt:
      # Needs $ because it uses an f-string
      - role: user
        content: $ f"The temperature is {steps[0].input.temp}°C"
      
      # No $ needed - plain text
      - role: user
        content: Tell me about the weather

  - evaluate:
      # Needs $ because it references step data
      input: $ steps[0].output
      
      # Needs $ because it's a Python expression
      condition: $ len(steps[0].input.text) > 100
```