sirius.tagliatelle.compiler

Class CompilationContext

java.lang.Object

sirius.tagliatelle.compiler.CompilationContext

public class CompilationContext
extends Object

Provides a context for compiling a .pasta file.

The main responsibility is to collect all errors or warnings and to provide the stack context (the names of all arguments and local variables).

Constructor Summary

Constructors

Constructor and Description
CompilationContext(Template template, CompilationContext parent) Creates a new context for the given template and parent context.

Method Summary

Modifier and Type	Method and Description
void	error(parsii.tokenizer.Position pos, String message, Object... params) Records an error for the given position.
Optional<sirius.kernel.commons.Tuple<Class<?>,Integer>>	findGlobal(String variableName) Tries to resolve a variable name into an environment index.
Optional<sirius.kernel.commons.Tuple<Class<?>,Integer>>	findLocal(String variableName) Tries to resolve a variable name into a stack location.
TagHandler	findTagHandler(parsii.tokenizer.Char position, String tagName) Resolves a tag name like i:if into a TagHandler.
List<parsii.tokenizer.ParseError>	getErrors() Returns all errors and warnings collected during the compilation.
int	getStackDepth() Returns the maximum stack depth required when rendering this template.
Template	getTemplate() Returns the template being compiled.
Emitter	inlineTemplate(parsii.tokenizer.Position startOfTag, Template template, Function<String,Expression> arguments, Function<String,Emitter> blocks) Inlines the requested template into the current one.
Emitter	invokeTemplate(parsii.tokenizer.Position position, Template template, Function<String,Expression> arguments, Map<String,Emitter> blocks) Generates an emitter which invokes the given template at runtime.
void	pop(parsii.tokenizer.Position position) Pops a local off the stack.
int	push(parsii.tokenizer.Position position, String name, Class<?> type) Pushes a local variable on the stack, so that it can be resolved later.
Class<?>	resolveClass(parsii.tokenizer.Position position, String typeName) Resolve a string (name) into a java class and reports an error if no matching class was found.
Optional<Template>	resolveTemplate(parsii.tokenizer.Position position, String name) Resolves the given name into a template.
int	stackAlloc() Allocates a stack position for an argument or local variable.
String	toString()
Optional<Class<?>>	tryResolveClass(String typeName) Tries to resolve a string (name) into a java class.
void	warning(parsii.tokenizer.Position pos, String message, Object... params) Records a warning for the given position.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CompilationContext

public CompilationContext(@Nonnull
                          Template template,
                          @Nullable
                          CompilationContext parent)

Creates a new context for the given template and parent context.

Parameters:

template - the template which is being compiled

parent - the parent context if the template is compiled because it is invoked by another template being compiled

Method Detail

getTemplate

public Template getTemplate()

Returns the template being compiled.

Returns:

the template which is currently being compiled

stackAlloc

public int stackAlloc()

Allocates a stack position for an argument or local variable.

For known and resolveable variables, this is automatically handled by push(Position, String, Class).

However, when a template is inlined into another, we also have to transfer locals to a new stack location and might also create new intermediate locals for now inlined arguments (because we must not evaluate non-constant expressions more thant once).

Returns:

the stack location to use

push

public int push(parsii.tokenizer.Position position,
                String name,
                Class<?> type)

Pushes a local variable on the stack, so that it can be resolved later.

Parameters:

position - the position where the local is defined - mainly used for error reporting

name - the name of the variable

type - the type of the variable

Returns:

the stack index of the variable

pop

public void pop(parsii.tokenizer.Position position)

Pops a local off the stack.

Note that this will only reduce the visibility of the variable but not free up the technical stack location. We only used each stack location once, to greatly simplify inlining.

Parameters:

position - the position which caused the pop - mainly used for error reporting

getStackDepth

public int getStackDepth()

Returns the maximum stack depth required when rendering this template.

Returns:

the maximal required stack depth to render this template

findLocal

public Optional<sirius.kernel.commons.Tuple<Class<?>,Integer>> findLocal(String variableName)

Tries to resolve a variable name into a stack location.

Parameters:

variableName - the name of the variable

Returns:

the type and the stack location of the variable or an empty optional, if no such variable exists

findGlobal

public Optional<sirius.kernel.commons.Tuple<Class<?>,Integer>> findGlobal(String variableName)

Tries to resolve a variable name into an environment index.

Parameters:

variableName - the variable to resolve

Returns:

the type and the index in the environment list or an empty optional, if no such variable exists

error

public void error(parsii.tokenizer.Position pos,
                  String message,
                  Object... params)

Records an error for the given position.

Parameters:

pos - the position where the error occured

message - the message to show

params - the formatting parameters applied to the message

warning

public void warning(parsii.tokenizer.Position pos,
                    String message,
                    Object... params)

Records a warning for the given position.

Parameters:

pos - the position where the warning occured

message - the message to show

params - the formatting parameters applied to the message

getErrors

public List<parsii.tokenizer.ParseError> getErrors()

Returns all errors and warnings collected during the compilation.

Returns:

a list of all errors and warnings

findTagHandler

public TagHandler findTagHandler(parsii.tokenizer.Char position,
                                 String tagName)

Resolves a tag name like i:if into a TagHandler.

There are mainly two types of tags. Built in ones, which start with i: and user defined tag libraries which start with an arbitrary prefix.

Parameters:

position - the position where the tag was detected

tagName - the name of the tag to resolve

Returns:

a tag handler when processes the referenced tag or null to indicate that this tag is unhandled.

resolveTemplate

public Optional<Template> resolveTemplate(parsii.tokenizer.Position position,
                                          String name)
                                   throws CompileException

Resolves the given name into a template.

If the template isn't compiled yet and directly or indirectly references the template currently being compiled, an appropriate exception is thrown to avoid infinite recursion.

Parameters:

position - the position where the template was referenced

name - the name of the template to resolve

Returns:

the resolved template or an empty optional to signal, that no matching template was found

Throws:

CompileException - if case of a compilation error when compiling the referenced template

invokeTemplate

public Emitter invokeTemplate(parsii.tokenizer.Position position,
                              Template template,
                              Function<String,Expression> arguments,
                              Map<String,Emitter> blocks)

Generates an emitter which invokes the given template at runtime.

Note that only the template name, not the template itself is stored, so that modifications of the referenced template will be detected and applied.

Parameters:

position - the position where the invokation took place

template - the template to call

arguments - the arguments passed to the template

blocks - the emitter blocks passed to the template

Returns:

an appropriate emitter which invokes the template with the given argument expressions at runtime

inlineTemplate

public Emitter inlineTemplate(parsii.tokenizer.Position startOfTag,
                              Template template,
                              Function<String,Expression> arguments,
                              Function<String,Emitter> blocks)

Inlines the requested template into the current one.

Note that the current state and content of the given template is used and that no further modifications of the referenced template are reflected (until the current template is recompiled). So this should only be used for static templates, not for ones modified by the user.

Note however, that aggressive optimizations are enabled by this approach as all constant arguments are propagated to the referenced template. Also all emitter blocks passed to the template are resolved and propagated during compilation.

As constant expressions and constant conditional emitters are optimized during the last phase of the compilation, this might yield in a much faster and more condense final template, especially if many configuration flags, as e.g. in the wondergem components, are present.

Parameters:

startOfTag - the position where the invokation took place

template - the template to call

arguments - the arguments passed to the template

blocks - the emitter blocks passed to the template

Returns:

an emitter which is basically a copy of the referenced template, where all arguments and emitter blocks haven been propagated so that the final and global optimization phase will be very effective

resolveClass

public Class<?> resolveClass(parsii.tokenizer.Position position,
                             String typeName)

Resolve a string (name) into a java class and reports an error if no matching class was found.

Next to the classic Class.forName this also supports aliases like String for java.lang.String.

Parameters:

position - the position for error reporting

typeName - the type name to resolve

Returns:

a Java class for the given type name

See Also:

Tagliatelle.getClassAliases()

tryResolveClass

public Optional<Class<?>> tryResolveClass(String typeName)

Tries to resolve a string (name) into a java class.

Next to the classic Class.forName this also supports aliases like String for java.lang.String.

Parameters:

typeName - the type name to resolve

Returns:

a Java class for the given type name wrapped as optional or an empty optional, if no matching class was found.

See Also:

Tagliatelle.getClassAliases()

toString

public String toString()

Overrides:

toString in class Object