sd-prompt-parser

sd-prompt-parser is a simple JS library for parsing Stable Diffusion prompts with custom syntax.

The syntax is designed to be used on frontends with one text input.

API

import { parse, split, stringify } from 'sd-prompt-parser';

const prompt = "tag1, -tag2, -(tag3, -tag4) <lora:lora1> <custom:modifiers>";

// AST of the prompt above
// IMPORTANT: `parse` may throw.
const parsed_prompt = parse(prompt);

// AST of positive and negative prompts
const [parsed_pos, parsed_neg] = split(parsed_prompt);

// "tag1, (tag4)<lora:lora1><custom:modifiers>"
console.log(stringify(parsed_pos));

// "tag2, (tag3)<lora:lora1><custom:modifiers>"
console.log(stringify(parsed_neg));

// "tag1, (tag4)<lora:lora1>(custom modifier: custom, modifiers)"
console.log(stringify(parsed_pos, {
    modifierHandler(args) {
        // Supported return types:
        // - `string[]`: the arguments of the modifier is substituted.
        // - `string`: the modifier is substituted to the string.
        // - `null` and `undefined`: removed.
        if(args[0] === 'lora') return args;
        return `(custom modifier: ${args.join(', ')})`;
    }
}));

Syntax

Simple tags

tag1, tag2, -tag3, -tag4, tag5

This translates to:

• Positive: tag1, tag2, tag5
• Negative: tag3, tag4

Attentions

(tag1, -tag2), -(tag3, -tag4), (tag5, -tag6, (tag7): 2)

This translates to:

• Positive: (tag1), (tag4), (tag5, (tag7):2)
• Negative: (tag2), (tag3), (tag6:2)

Modifiers

<lora:name1:weight1> -<custom:name2:weight2>

This translates to:

• Positive: <lora:name1:weight1>
• Negative: <custom:name2:weight2>