EEx v1.5.0 EEx.Engine behaviour View Source
Basic EEx engine that ships with Elixir.
An engine needs to implement four functions:
init(opts)- returns the initial bufferhandle_body(quoted)- receives the final built quoted expression, should do final post-processing and return a quoted expression.handle_text(buffer, text)- it receives the buffer, the text and must return a new quoted expression.handle_expr(buffer, marker, expr)- it receives the buffer, the marker, the expr and must return a new quoted expression.The marker is what follows exactly after
<%. For example,<% foo %>has an empty marker, but<%= foo %>has"="as marker. The allowed markers so far are:""and"=".Read
handle_expr/3below for more information about the markers implemented by default by this engine.
EEx.Engine can be used directly if one desires to use the
default implementations for the functions above.
Link to this section Summary
Functions
Handles assigns in quoted expressions
The default implementation simply returns the given expression
Implements expressions according to the markers
The default implementation simply concatenates text to the buffer
Returns an empty string as initial buffer
Link to this section Functions
Handles assigns in quoted expressions.
A warning will be printed on missing assigns. Future versions will raise.
This can be added to any custom engine by invoking
handle_assign/1 with Macro.prewalk/2:
def handle_expr(buffer, token, expr) do
expr = Macro.prewalk(expr, &EEx.Engine.handle_assign/1)
EEx.Engine.handle_expr(buffer, token, expr)
endThe default implementation simply returns the given expression.
Implements expressions according to the markers.
<% Elixir expression - inline with output %>
<%= Elixir expression - replace with result %>All other markers are not implemented by this engine.
The default implementation simply concatenates text to the buffer.
Returns an empty string as initial buffer.