llama

Lisp-Like Application Markup (Acronym)

Why

XML is <verbose></verbose> due to its closing tags and its lack of a macro preprocessor. I want an XML preprocessor that is very close to XML (declarative, structured, light on syntax) but that allows me to describe documents in fewer characters.

What

Llama is a lisp-like data description language, and a compiler for that language targeting XML, implemented in Javascript.

The following Llama:

(Table
  (_.columns
    (let ([(Column name flex)
           (Table.Column (('name name) ('flex flex)
                          (dataKey name) (sortable true)))])
      (Column ticketNumber 0.5)
      (Column summary 2.7)
      (Column status 0.2)
      (Column created 0.7)
      (Column closed 0.7))))

expands to the following XML:

<Table>
  <_.columns>
    <Table.Column name="ticketNumber" flex="0.5" dataKey="ticketNumber"
                  sortable="true"/>
    <Table.Column name="summary" flex="2.7" dataKey="summary" sortable="true"/>
    <Table.Column name="status" flex="0.2" dataKey="status" sortable="true"/>
    <Table.Column name="created" flex="0.7" dataKey="created" sortable="true"/>
    <Table.Column name="closed" flex="0.7" dataKey="closed" sortable="true"/>
  </_.columns>
</Table>

and the following Llama:

(Table.RowTemplate ((name filters))
  (let ([(setter name) ((conc set. name) (conc @ name))]
        [Cell (Table.Cell ((factory label) (on.click {Ref onClick})
                           (setter text) (setter tooltip) (setter style)))])
    (repeat 10 Cell)))

expands to the following XML:

<Table.RowTemplate name="filters">
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
  <Table.Cell factory="label" on.click="{Ref onClick}" set.text="@text"
              set.tooltip="@tooltip" set.style="@style" />
</Table.RowTemplate>

How

Using the Playground

Open index.html in a web browser. The left panel is an entry accepting Llama. When valid Llama is entered, the resulting output will appear on the right. Any of the following outputs may be selected:

Tokens: the tokens lexed from the input string
Parse Tree: the raw data structure parsed from the lexer tokens
Evaluated Tree: the AST after macro expansion and expression evaluation
XML Nodes: a javascript representation of an XML interpretation of the evaluated AST.
XML Text: the final XML output

Using `llama.js`

bin/llama.js is a node script that reads llama from a specified input file or from standard input, and prints the resulting XML to standard output.

Using node.js, etc.

Each .js file in llama/ is an Asynchronous Module Definition (AMD) module. You can use requirejs, or any other conforming AMD module loader, to import the llama source modules in node, the browser, or your javascript environment of choice.

More

Grammar

A Llama value is any of the following productions:

datum  ::=   STRING
        |    NUMBER
        |    SYMBOL
        |    COMMENT
        |    list
        |    quote

list   ::=   "(" datum* ")"
        |    "[" datum* "]"
        |    "{" datum* "}"

quote  ::=  QUOTE datum

STRING      ::=  /"(?:[^"\\]|\\.)*"/
WHITESPACE  ::=  /\s+,/
NUMBER      ::=  /\d[^;'\s()[\]{},]*/
SYMBOL      ::=  /[^;'\d\s()[\]{},][^;'\s()[\]{},]*/
QUOTE       ::=  /'/
COMMENT     ::=  /;[^\n]*(?:\n|$)/

where WHITESPACE and COMMENT tokens are ignored. Note that the comma is considered whitespace.

The `let` Macro

The let macro allows for the definition of local name bindings and procedures. For example, an alias can be given for a long value:

(App
  (StaticData
    (let ([matrix (Matrix ((rows 5) (columns 5))
                    (Matrix.rows
                      (let ([row (Matrix.Row 
                                   (Int 0) (Int 0) (Int 0) (Int 0) (Int 0))])
                        row row row row row)))])
      (StaticDatum ((name initialFoo)) matrix)
      (StaticDatum ((name initialBar)) matrix)
      (StaticDatum ((name initialBaz)) matrix)
      (StaticDatum ((name initialZoo)) matrix)
      (StaticDatum ((name initialWho)) matrix)
      (StaticDatum ((name initialYou)) matrix))))

That's a lot shorter than the resulting XML:

<App>
  <StaticData>
    <StaticDatum name="initialFoo">
      <Matrix rows="5" columns="5">
        <Matrix.rows>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
        </Matrix.rows>
      </Matrix>
    </StaticDatum>
    <StaticDatum name="initialBar">
      <Matrix rows="5" columns="5">
        <Matrix.rows>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
        </Matrix.rows>
      </Matrix>
    </StaticDatum>
    <StaticDatum name="initialBaz">
      <Matrix rows="5" columns="5">
        <Matrix.rows>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
        </Matrix.rows>
      </Matrix>
    </StaticDatum>
    <StaticDatum name="initialZoo">
      <Matrix rows="5" columns="5">
        <Matrix.rows>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
        </Matrix.rows>
      </Matrix>
    </StaticDatum>
    <StaticDatum name="initialWho">
      <Matrix rows="5" columns="5">
        <Matrix.rows>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
        </Matrix.rows>
      </Matrix>
    </StaticDatum>
    <StaticDatum name="initialYou">
      <Matrix rows="5" columns="5">
        <Matrix.rows>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
          <Matrix.Row>
            <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int> <Int>0</Int>
          </Matrix.Row>
        </Matrix.rows>
      </Matrix>
    </StaticDatum>
  </StaticData>
</App>

That Llama can be made even simpler by defining some procedures, another feature of the let macro:

(StaticData
    (let ([matrix (Matrix ((rows 5) (columns 5))
                    (Matrix.rows
                      (let ([row (Matrix.Row 
                                   (Int 0) (Int 0) (Int 0) (Int 0) (Int 0))])
                        row row row row row)))]
          [(staticMatrix name) (StaticDatum (('name name)) matrix)])
      (staticMatrix initialFoo)
      (staticMatrix initialBar)
      (staticMatrix initialBaz)
      (staticMatrix initialZoo)
      (staticMatrix initialWho)
      (staticMatrix initialYou))))

The real power of let procedures, though, is the ability to pattern match against sequences using the ellipsis. "..." stands for "zero or more" of whatever precedes it. For example:

(RowTemplate.cells
  (let ([(Cell expr (attr value) ...)
         (Table.Cell ((factory label) (set.text expr) (attr value) ...))])
    (Cell @name)
    (Cell @email)
    (Cell @rank)
    ; notice the extra attribute(s) in the following:
    (Cell @salary (secret true))
    (Cell @party (secret false) (annotations deprecated))))

The Cell procedure will take zero or more trailing arguments each matching (attr value), and append them to the attributes section of the expanded form.

The ... can even be nested, though it's uncommon:

(Example
  (let ([(AllAliases (person alias ...) ...) (Aliases (Alias alias) ... ...)])
    (AllAliases (Robert G-Unit Bob Bert)
                (Steve  Steve-O V-unit)
                (Mary   Steve)
                (Fred   Ed))))

expands to:

<Example>
  <Aliases>
    <Alias>G-Unit</Alias>
    <Alias>Bob</Alias>
    <Alias>Bert</Alias>
    <Alias>Steve-O</Alias>
    <Alias>V-unit</Alias>
    <Alias>Steve</Alias>
    <Alias>Ed</Alias>
  </Aliases>
</Example>

Built-in Procedures and Macros

(conc args ...): Concatenate the arguments, which can be any mix of strings and symbols, and return a string that is their concatenation.
(repeat count datum): Splice count copies of datum into the enclosing list.
(comment args ...): Ignore the form. This gives a convenient way to comment out blocks of code in a nestable way.

Name		Name	Last commit message	Last commit date
Latest commit History 37 Commits
bin		bin
llama		llama
.jshintrc		.jshintrc
.nojekyll		.nojekyll
CREDIT.md		CREDIT.md
LICENSE		LICENSE
README.md		README.md
index.html		index.html
llama.jpg		llama.jpg
playground.js		playground.js
require.js		require.js

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Repository files navigation

llama

Why

What

How

Using the Playground

Using `llama.js`

Using node.js, etc.

More

Grammar

The `let` Macro

Built-in Procedures and Macros

About

Releases

Packages

Languages

License

dgoffredo/llama

Folders and files

Latest commit

History

Repository files navigation

llama

Why

What

How

Using the Playground

Using llama.js

Using node.js, etc.

More

Grammar

The let Macro

Built-in Procedures and Macros

About

Resources

License

Stars

Watchers

Forks

Releases

Packages 0

Languages

Using `llama.js`

The `let` Macro

Packages