Dynamic scaling of ingredients

Baking often requires precise measurements when it comes to ingredients. I find myself doing arithmetic in these scenarios:

• unit conversions (temperature and mass <–> volume)
• scaling recipes by a constant factor
• scaling recipes by an ingredient
  • Example: I have a recipe for bread that requires 2500g of flour, but I only have 2000g.

I want to dynamically create some rules that capture data via regex. For example,

text = "2500g of flour"
weightRegex = /(\d+)\s?(g)/

and parse the captured data [value: 2000, unit: g] into a table. Then, some Airtable-like UI should exist allowing me to arbitrarily transform the captured data. I should be able to replace the text in the ingredients list and the recipe text.