Nim-mustache

Mustache in Nim.

Nim-mustache is a Nim implementation of Mustache. Mustache is a logic-less templating system inspired by ctemplate and et. Mustache "emphasizes separating logic from presentation: it is impossible to embed application logic in this template language."

Status

Nim-mustache is in beta stage. Welcome to contribute, comment, and report issues. ❤️

Features

• ✨ Support Static Text.
• ✨ Support {{Variables}}.
• ✨ Support {{# Section }} {{/ Section }}.
• ✨ Support {{^ InvertedSection }} {{/ InvertedSection }}.
• ✨ Support {{! Comments }}.
• ✨ Support {{=<% %>=}} <% SetDelimiter %>.
• ✨ Support {{> Partial }}.
• ✨ Support Lambda.
• ✨ Passed all mustache specs.

Getting Started

Nim-mustache requires Nim >= 0.20.

$ nimble install mustache

Usage

# Step 1.
import mustache, tables

# Step 2.
var c = newContext()
c["i"] = 1
c["f"] = 1.0
c["s"] = "hello world"
c["a"] = @[{"k": "v"}.toTable]
c["t"] = {"k": "v"}.toTable
c["l"] = proc(s: string, c: Context): string = "<b>" & s.render(c) & "</b>"

# Step 3.
let s = """
{{i}} {{f}} {{s}}
{{#a}}
  {{k}}
{{/a}}

{{#t}}
  {{k}}
{{/t}}

{{#l}}
  {{s}}
{{/l}}
"""
echo(s.render(c))

Advanced Usage

Set Arbitrary Objects in Context

Consider you have your own object Stock.

type Stock = object
  name*: string
  price*: int

let stock = Stock(name: "NIM", price: 1000)

It would be convenient if you can set it to context:

let c = newContext()
c["stock"] = stock
let s = "{{#stock}}{{name}}: {{price}}{{/stock}}"
echo(s.render(c))

The trick is to overwrite castValue method. By default, this method can cast int, string, seq[Value], table[string, Value], etc. Below is an example of how to overwrite it.

method castValue(value: Stock): Value =
  let newValue = new(Table[string, Value])
  result = Value(kind: vkTable, vTable: newValue)
  newValue["name"] = value.name.castValue
  newValue["price"] = value.price.castValue

Change Partials Searching Dir

By default, partials are located in cwd.

$ ls
main.mustache    partial.mustache
$ cat main.mustache
{{> partial}}

But what if mustache files are in other locations?

$ pwd
/tmp/path/to
$ ls -R
main.mustache
templates/partial.mustache

In this case, You can specify other searching dirs:

let c = newContext(searchDirs=@["/tmp/path/to/templates", "./"])
let s = readFile("main.mustache")
echo(s.render(c))

Develop

Build the binary.

$ nimble build

Run test cases.

$ nimble test

Changelog

• v0.2.0, 20 Sep 2019, support setting arbitrary objects in context.
• v0.1.0, 19 Sep 2019, initial release.

Alternatives

• moustachu. Moustachu doesn't implement some mustache features, such as lambda, set delimiters, while Nim-mustache supports all mustache features.

References

• Spec
• Syntax