Overview - erlydtl - Introduction and notes on creating, compiling and using ErlyDTL templates

Updated Feb 28, 2009 by emmiller
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Overview

Introduction and notes on creating, compiling and using ErlyDTL templates

Template compilation:

erlydtl exports compile/2 and compile/3:

erlydtl:compile(Input, Module::atom()) ->
    ok | {error, Reason::terms())}

erlydtl:compile(Input, Module::atom(), Options::PropertiesList) -> 
    ok | {error, Reason::term()}

When Input is a string, it is interpreted as a filename. When Input is a binary, it is interpreted as the template code; in this case, note that the generated bytecode is then loaded directly into memory, and no beam file gets generated.

Options include:

out_dir - Output directory for BEAM files (by default no BEAM files are created)
vars - Variables (and their values) to evaluate at compile-time rather than render-time (defaults to []).
force_recompile - Recompile the module even if the source's checksum has not changed. Useful for debugging.
compiler_options - Proplist passed directly to compiler:forms/2 (defaults to [verbose, report_errors]
doc_root - Included template paths will be relative to this directory; defaults to the compiled template's directory.
custom_tags_dir - Directory of DTL files (no extension) includable as tags. E.g. if $custom_tags_dir/foo contains <b>{% bar %}</b>, then {% foo bar=100 %}" will evaluate to 100`. Get it?
reader - {module, function} tuple that takes a path to a template and returns a binary with the file contents. Defaults to {file, read_file}. Useful for reading templates from a network resource.

Usage (of a compiled template):

my_compiled_template:render(Variables) -> {ok, Result::iolist()} | {error, Err::string()}

Variables is a proplist, dict, gb_tree, or a parameterized module (whose method names correspond to variable names). The variable values can be atoms, strings, binaries, or (nested) variables.

my_compiled_template:source() -> {Filename::string(), CheckSum::string()}

Name and checksum of the original template file.

my_compiled_template:dependencies() -> [{Filename::string(), CheckSum::string()}]

List of names/checksums of templates included by the original template file. Useful for frameworks that recompile a template only when the template's dependencies change.

Examples:

Run from Erlang interactive shell:

erlydtl_functional_tests:run_tests().

this compiles the example templates, puts the generated beamfiles into the ebin folder and the rendered output into examples/rendered_output folder.

Tests:

Run from Unix shell:

make test