#Toy Template Engine

##Introduction

This is a toy project for learning how to write a template engine. I made it just for fun. It will be updated continually. The basic part of this project is mainly consulted This blog post and Jinja2 template engine.

##Grammar Design

The template grammar contains two type of tags.

• {{ ... }} for Expression
• {% ... %} for Statement

###Expression

Literals: *(NOT_IMPLEMENT)*all literals of pythonn is valid. For example:

• string: "Hello world"
• number: 43, 3.14159
• list: [1, 2, 3]
• dict: {'key': value}
• tuple: (12, 33)
• boolean: True, False

Math *(NOT_IMPLEMENT)*The following operators is supported: +, -, *, /, **, %, //

Comparisons *(NOT_IMPLEMENT)*The following operators is supported: ==, >=, <=, !=, >, <

Logic *(NOT_IMPLEMENT)*The following operators is supported: and, or, not, ()

Other *(NOT_IMPLEMENT)*The following operators is supported: in, is,

[] for getting an attribute of an object,

~ for string concatenates,

() for calling a callable object.

###Statement

If statement: *(NOT_IMPLEMENT)*The if statement is similar to python. elif and else are optional. For example:

{% if condition1 %}
    branch 1
{% elif condition2 %}
    branch 2
{% else %}
    branch else
{% endif %}

For statement: *(NOT_IMPLEMENT)*The for statement is just like below:

{% for item in items%}
    The item in items is {{item}}.
{% end for%}