overview: |
  Section tags and End Section tags are used in combination to wrap a section
  of the template for iteration.

  These tags' content MUST be a non-whitespace character sequence NOT
  containing the current closing delimiter; each Section tag MUST be followed
  by an End Section tag with the same content within the same section.

  This tag's content names the data to replace the tag.  Name resolution is as
  follows:
    1) If the name is a single period (.), the data is the item currently
    sitting atop the context stack. Skip the rest of these steps.
    2) Split the name on periods; the first part is the name to resolve, any
    remaining parts should be retained.
    3) Walk the context stack from top to bottom, finding the first context
    that is a) a hash containing the name as a key OR b) an object responding
    to a method with the given name.
    4) If the context is a hash, the data is the value associated with the
    name.
    5) If the context is an object and the method with the given name has an
    arity of 1, the method SHOULD be called with a String containing the
    unprocessed contents of the sections; the data is the value returned.
    6) Otherwise, the data is the value returned by calling the method with
    the given name.
    7) If any name parts were retained in step 1, each should be resolved
    against a context stack containing only the result from the former
    resolution.  If any part fails resolution, the result should be considered
    falsey, and should interpolate as the empty string.

  If the data is not of a list type, it is coerced into a list as follows: if
  the data is truthy (e.g. `!!data == true`), use a single-element list
  containing the data, otherwise use an empty list.

  For each element in the data list, the element MUST be pushed onto the
  context stack, the section MUST be rendered, and the element MUST be popped
  off the context stack.

  Section and End Section tags SHOULD be treated as standalone when
  appropriate.
tests:
  - name: Truthy
    desc: Truthy sections should have their contents rendered.
    data: { boolean: true }
    template: '"{{#boolean}}This should be rendered.{{/boolean}}"'
    expected: '"This should be rendered."'

  - name: Falsey
    desc: Falsey sections should have their contents omitted.
    data: { boolean: false }
    template: '"{{#boolean}}This should not be rendered.{{/boolean}}"'
    expected: '""'

  - name: Null is falsey
    desc: Null is falsey.
    data: { "null": null }
    template: '"{{#null}}This should not be rendered.{{/null}}"'
    expected: '""'

  - name: Context
    desc: Objects and hashes should be pushed onto the context stack.
    data: { context: { name: 'Joe' } }
    template: '"{{#context}}Hi {{name}}.{{/context}}"'
    expected: '"Hi Joe."'

  - name: Parent contexts
    desc: Names missing in the current context are looked up in the stack.
    data: { a: "foo", b: "wrong", sec: { b: "bar" }, c : { d : "baz" } }
    template: '"{{#sec}}{{a}}, {{b}}, {{c.d}}{{/sec}}"'
    expected: '"foo, bar, baz"'

  - name: Variable test
    desc: |
      Non-false sections have their value at the top of context,
      accessible as {{.}} or through the parent context. This gives
      a simple way to display content conditionally if a variable exists.
    data: { foo: "bar" }
    template: '"{{#foo}}{{.}} is {{foo}}{{/foo}}"'
    expected: '"bar is bar"'

  - name: List Contexts
    desc: All elements on the context stack should be accessible within lists.
    data:
      tops:
        - tname:
            upper: "A"
            lower: "a"
          middles:
            - mname: "1"
              bottoms:
                - bname: "x"
                - bname: "y"
    template: '{{#tops}}{{#middles}}{{tname.lower}}{{mname}}.{{#bottoms}}{{tname.upper}}{{mname}}{{bname}}.{{/bottoms}}{{/middles}}{{/tops}}'
    expected: 'a1.A1x.A1y.'

  - name: Deeply Nested Contexts
    desc: All elements on the context stack should be accessible.
    data:
      a: { one: 1 }
      b: { two: 2 }
      c: { three: 3, d : { four : 4, five : 5 } }
    template: |
      {{#a}}
      {{one}}
      {{#b}}
      {{one}}{{two}}{{one}}
      {{#c}}
      {{one}}{{two}}{{three}}{{two}}{{one}}
      {{#d}}
      {{one}}{{two}}{{three}}{{four}}{{three}}{{two}}{{one}}
      {{#five}}
      {{one}}{{two}}{{three}}{{four}}{{five}}{{four}}{{three}}{{two}}{{one}}
      {{one}}{{two}}{{three}}{{four}}{{.}}6{{.}}{{four}}{{three}}{{two}}{{one}}
      {{one}}{{two}}{{three}}{{four}}{{five}}{{four}}{{three}}{{two}}{{one}}
      {{/five}}
      {{one}}{{two}}{{three}}{{four}}{{three}}{{two}}{{one}}
      {{/d}}
      {{one}}{{two}}{{three}}{{two}}{{one}}
      {{/c}}
      {{one}}{{two}}{{one}}
      {{/b}}
      {{one}}
      {{/a}}
    expected: |
      1
      121
      12321
      1234321
      123454321
      12345654321
      123454321
      1234321
      12321
      121
      1

  - name: List
    desc: Lists should be iterated; list items should visit the context stack.
    data: { list: [ { item: 1 }, { item: 2 }, { item: 3 } ] }
    template: '"{{#list}}{{item}}{{/list}}"'
    expected: '"123"'

  - name: Empty List
    desc: Empty lists should behave like falsey values.
    data: { list: [ ] }
    template: '"{{#list}}Yay lists!{{/list}}"'
    expected: '""'

  - name: Doubled
    desc: Multiple sections per template should be permitted.
    data: { bool: true, two: 'second' }
    template: |
      {{#bool}}
      * first
      {{/bool}}
      * {{two}}
      {{#bool}}
      * third
      {{/bool}}
    expected: |
      * first
      * second
      * third

  - name: Nested (Truthy)
    desc: Nested truthy sections should have their contents rendered.
    data: { bool: true }
    template: "| A {{#bool}}B {{#bool}}C{{/bool}} D{{/bool}} E |"
    expected: "| A B C D E |"

  - name: Nested (Falsey)
    desc: Nested falsey sections should be omitted.
    data: { bool: false }
    template: "| A {{#bool}}B {{#bool}}C{{/bool}} D{{/bool}} E |"
    expected: "| A  E |"

  - name: Context Misses
    desc: Failed context lookups should be considered falsey.
    data: { }
    template: "[{{#missing}}Found key 'missing'!{{/missing}}]"
    expected: "[]"

  # Implicit Iterators

  - name: Implicit Iterator - String
    desc: Implicit iterators should directly interpolate strings.
    data:
      list: [ 'a', 'b', 'c', 'd', 'e' ]
    template: '"{{#list}}({{.}}){{/list}}"'
    expected: '"(a)(b)(c)(d)(e)"'

  - name: Implicit Iterator - Integer
    desc: Implicit iterators should cast integers to strings and interpolate.
    data:
      list: [ 1, 2, 3, 4, 5 ]
    template: '"{{#list}}({{.}}){{/list}}"'
    expected: '"(1)(2)(3)(4)(5)"'

  - name: Implicit Iterator - Decimal
    desc: Implicit iterators should cast decimals to strings and interpolate.
    data:
      list: [ 1.10, 2.20, 3.30, 4.40, 5.50 ]
    template: '"{{#list}}({{.}}){{/list}}"'
    expected: '"(1.1)(2.2)(3.3)(4.4)(5.5)"'

  - name: Implicit Iterator - Array
    desc: Implicit iterators should allow iterating over nested arrays.
    data:
      list: [ [1, 2, 3], ['a', 'b', 'c'] ]
    template: '"{{#list}}({{#.}}{{.}}{{/.}}){{/list}}"'
    expected: '"(123)(abc)"'

  - name: Implicit Iterator - HTML Escaping
    desc: Implicit iterators with basic interpolation should be HTML escaped.
    data:
      list: [ '&', '"', '<', '>' ]
    template: '"{{#list}}({{.}}){{/list}}"'
    expected: '"(&amp;)(&quot;)(&lt;)(&gt;)"'

  - name: Implicit Iterator - Triple mustache
    desc: Implicit iterators in triple mustache should interpolate without HTML escaping.
    data:
      list: [ '&', '"', '<', '>' ]
    template: '"{{#list}}({{{.}}}){{/list}}"'
    expected: '"(&)(")(<)(>)"'

  - name: Implicit Iterator - Ampersand
    desc: Implicit iterators in an Ampersand tag should interpolate without HTML escaping.
    data:
      list: [ '&', '"', '<', '>' ]
    template: '"{{#list}}({{&.}}){{/list}}"'
    expected: '"(&)(")(<)(>)"'

  - name: Implicit Iterator - Root-level
    desc: Implicit iterators should work on root-level lists.
    data: [ { value: 'a' }, { value: 'b' } ]
    template: '"{{#.}}({{value}}){{/.}}"'
    expected: '"(a)(b)"'

  # Dotted Names

  - name: Dotted Names - Truthy
    desc: Dotted names should be valid for Section tags.
    data: { a: { b: { c: true } } }
    template: '"{{#a.b.c}}Here{{/a.b.c}}" == "Here"'
    expected: '"Here" == "Here"'

  - name: Dotted Names - Falsey
    desc: Dotted names should be valid for Section tags.
    data: { a: { b: { c: false } } }
    template: '"{{#a.b.c}}Here{{/a.b.c}}" == ""'
    expected: '"" == ""'

  - name: Dotted Names - Broken Chains
    desc: Dotted names that cannot be resolved should be considered falsey.
    data: { a: { } }
    template: '"{{#a.b.c}}Here{{/a.b.c}}" == ""'
    expected: '"" == ""'

  # Whitespace Sensitivity

  - name: Surrounding Whitespace
    desc: Sections should not alter surrounding whitespace.
    data: { boolean: true }
    template: " | {{#boolean}}\t|\t{{/boolean}} | \n"
    expected: " | \t|\t | \n"

  - name: Internal Whitespace
    desc: Sections should not alter internal whitespace.
    data: { boolean: true }
    template: " | {{#boolean}} {{! Important Whitespace }}\n {{/boolean}} | \n"
    expected: " |  \n  | \n"

  - name: Indented Inline Sections
    desc: Single-line sections should not alter surrounding whitespace.
    data: { boolean: true }
    template: " {{#boolean}}YES{{/boolean}}\n {{#boolean}}GOOD{{/boolean}}\n"
    expected: " YES\n GOOD\n"

  - name: Standalone Lines
    desc: Standalone lines should be removed from the template.
    data: { boolean: true }
    template: |
      | This Is
      {{#boolean}}
      |
      {{/boolean}}
      | A Line
    expected: |
      | This Is
      |
      | A Line

  - name: Indented Standalone Lines
    desc: Indented standalone lines should be removed from the template.
    data: { boolean: true }
    template: |
      | This Is
        {{#boolean}}
      |
        {{/boolean}}
      | A Line
    expected: |
      | This Is
      |
      | A Line

  - name: Standalone Line Endings
    desc: '"\r\n" should be considered a newline for standalone tags.'
    data: { boolean: true }
    template: "|\r\n{{#boolean}}\r\n{{/boolean}}\r\n|"
    expected: "|\r\n|"

  - name: Standalone Without Previous Line
    desc: Standalone tags should not require a newline to precede them.
    data: { boolean: true }
    template: "  {{#boolean}}\n#{{/boolean}}\n/"
    expected: "#\n/"

  - name: Standalone Without Newline
    desc: Standalone tags should not require a newline to follow them.
    data: { boolean: true }
    template: "#{{#boolean}}\n/\n  {{/boolean}}"
    expected: "#\n/\n"

  # Whitespace Insensitivity

  - name: Padding
    desc: Superfluous in-tag whitespace should be ignored.
    data: { boolean: true }
    template: '|{{# boolean }}={{/ boolean }}|'
    expected: '|=|'