tlang/source/tlang/compiler/typecheck/resolution.d

1043 lines
31 KiB
D

module tlang.compiler.typecheck.resolution;
import tlang.compiler.typecheck.core;
import tlang.misc.logging;
import tlang.compiler.symbols.data;
import std.string;
import std.conv : to;
import tlang.compiler.core;
import std.string : format;
import niknaks.functional : Predicate, predicateOf;
/**
* The resolver provides a mechanism to
* search the AST tree for all named
* entities.
*
* It provides various different lookup
* strategies for resolvbing recursively
* at various different levels etc.
*/
public final class Resolver
{
/**
* The root of everything; the `Program`
*/
private Program program;
/**
* Associated TypeChecker engine
*/
private TypeChecker typeChecker;
/**
* Constructs a new resolver with the given
* root program and the type checking instance
*
* Params:
* program = the root program
* typeChecker = the type checker instance
*/
this(Program program, TypeChecker typeChecker)
{
this.program = program;
this.typeChecker = typeChecker;
}
/**
* Generate the absolute full path of the given
* entity without specifying which anchor point
* to use.
*
* What this will do is call `generateName(Container, Entity)`
* with the container set to the `Program`,
* this will therefore cause the intended
* behavior described above - see the aforementioned
* method for the reason as to why this works
* out.
*
* This will climb the AST tree until it finds
* the containing `Module` of the given entity
* and then it will generate the name using
* that as the anchor - hence giving you the
* absolute path (because remember, a `Program`
* has no name, next best is the `Module`).
*
* Params:
* entity = The Entity to generate the full absolute path for
*
* Returns: The absolute full path
*/
public string generateNameBest(Entity entity)
{
assert(entity);
return generateName(this.program, entity);
}
/**
* Given an entity and a container this will
* generate the entity's full path relative
* to the given container.
*
* A special case is when the container is a
* `Program`, in that case the entity's containing
* `Module` will be found and the name will be
* generated relative to that. Since `Program`'s
* have no names, doing such a call gives you
* the absolute (full path) of the entity within
* the entire program as the `Module` is the
* second highest in the AST tree and first
* `Entity`-typed object, meaning first "thing"
* with a name.
*
* Params:
* relativeTo = the container to generate relative
* to
* entity = the entity to generate a name for
* Returns: the generated path
*/
public string generateName(Container relativeTo, Entity entity)
{
assert(relativeTo);
assert(entity);
// Special case (see doc)
if(cast(Program)relativeTo)
{
Container potModC = findContainerOfType(Module.classinfo, entity);
assert(potModC); // Should always be true (unless you butchered the AST)
Module potMod = cast(Module)potModC;
assert(potMod); // Should always be true (unless you butchered the AST)
return generateName(potMod, entity);
}
string[] name = generateName0(relativeTo, entity);
string path;
for (ulong i = 0; i < name.length; i++)
{
path ~= name[name.length - 1 - i];
if (i != name.length - 1)
{
path ~= ".";
}
}
return path;
}
/**
* Generates the components of the path from
* a given entity up to (and including) the
* given container. The latter implies that
* the given `Container` must also be a kind-of
* `Entity` such that a name can be generated
* from it.
*
* Params:
* relativeTo = the container to generate
* up to (inclusively)
* entity = the entity to start at
* Returns: an array of the named segments
* from the container-to-entity appearing in
* a left-to-right fashion. `null` is returned
* in the case that the given entity has no
* relation at all to the given container.
*/
private string[] generateName0(Container relativeTo, Entity entity)
{
Entity containerEntity = cast(Entity) relativeTo;
assert(containerEntity);
/**
* If the Entity and Container are the same then
* just returns its name
*/
if (relativeTo == entity)
{
return [containerEntity.getName()];
}
/**
* If the Entity is contained within the Container
*/
else if (isDescendant(relativeTo, entity))
{
string[] items;
Entity currentEntity = entity;
do
{
items ~= currentEntity.getName();
/**
* So far all objects we have being used
* of which are kind-of Containers are also
* and ONLY also kind-of Entity's hence the
* cast should never fail.
*
* This method is never called with,
* for example, a `Program` relativeTo.
*/
assert(cast(Entity) currentEntity.parentOf());
currentEntity = cast(Entity)(currentEntity.parentOf());
}
while (currentEntity != relativeTo);
/* Add the relative to container */
items ~= containerEntity.getName();
return items;
}
/**
* If not
*/
else
{
return null;
}
}
/**
* Returns `true` entity `e` is `c` or is within
* (contained under `c`), `false` otherwise
*
* Params:
* c = the `Container` to check against
* e = the `Entity` to check if it belongs
* to the container `c` either directly or
* indirectly (or if it IS the container `c`)
* Returns: `true` if so, `false` otherwise
*/
public bool isDescendant(Container c, Entity e)
{
/**
* If they are the same
*/
if (c == e)
{
return true;
}
/**
* If not, check descendancy
*/
else
{
Entity currentEntity = e;
do
{
DEBUG
(
format("c isdecsenat: %s", c)
);
DEBUG
(
format("currentEntity: %s", currentEntity)
);
Container parentOfCurrent = currentEntity.parentOf();
DEBUG
(
format("currentEntity(parent): %s", parentOfCurrent)
);
// If the parent of the currentEntity
// is what we were searching for, then
// yes, we found it to be a descendant
// of it
if(parentOfCurrent == c)
{
return true;
}
// Every other case, use current entity's parent
// as starting point and keep climbing
//
// This would also be null (and stop the search
// if we reached the end of the tree in a case
// where the given container to anchor by is
// the `Program` BUT was not that of a valid one
// that actually belonged to the same tree as
// the starting node. This becomes `null` because
// remember that a `Program` is not a kind-of `Entity`
currentEntity = cast(Entity)(parentOfCurrent);
}
while (currentEntity);
return false;
}
}
/**
* Performs a horizontal-level search of the given
* `Container`, returning a found `Entity` when
* the predicate supplied returns a positive
* verdict on said entity then we add an entry
* to the ref parameter
*
* Params:
* currentContainer = the container to search
* within
* predicate = the predicate to use
*/
public void resolveWithin(Container currentContainer, Predicate!(Entity) predicate, ref Entity[] collection)
{
DEBUG
(
format
(
"resolveWithin(cntnr=%s) entered",
currentContainer
)
);
Statement[] statements = currentContainer.getStatements();
DEBUG
(
format
(
"resolveWithin(cntnr=%s) container has statements %s",
currentContainer,
statements
)
);
foreach(Statement statement; statements)
{
Entity entity = cast(Entity) statement;
if(entity)
{
if(predicate(entity))
{
collection ~= entity;
}
}
}
}
/**
* Performs a horizontal-level search of the given
* `Container`, returning a found `Entity` when
* the predicate supplied returns a positive
* verdict on said entity then we return it.
*
* Params:
* currentContainer = the container to search
* within
* predicate = the predicate to use
* Returns: an `Entity` if found else `null`
*/
public Entity resolveWithin(Container currentContainer, Predicate!(Entity) predicate)
{
Entity[] foundEnts;
resolveWithin(currentContainer, predicate, foundEnts);
DEBUG(format("foundEnts: %s", foundEnts));
return foundEnts.length ? foundEnts[0] : null;
}
/**
* Creates a closure that captures the name
* requested and encodes a name-matching based
* logic in it
*
* Params:
* nameToMatch = the name the closure predicate
* should match to
*
* Returns: a `Predicate!(Entity)`
*/
private static Predicate!(Entity) derive_nameMatch(string nameToMatch)
{
/**
* A name-based search is simply something
* that would use the below closure as
* the searching predicate
*/
bool nameMatch(Entity entity)
{
bool result = cmp(entity.getName(), nameToMatch) == 0;
DEBUG(format("nameMatch(left=%s, right=%s) result: %s", nameToMatch, entity.getName(), result));
return result;
}
// TODO: Double check but yeah sure this will now
// allocate `name` on heap to prevent stack overwrite
// when called
return &nameMatch;
}
/**
* Performs a horizontal-based search of then
* provided `Container`, searching for any
* `Entity` which matches the given name.
* When a match is found we return
* immediately.
*
* Params:
* currentContainer = the container to
* search within
* name = the name to search for
* Returns: the found `Entity` or
* `null` nothing was found
*/
public Entity resolveWithin(Container currentContainer, string name)
{
// Apply search with custom name-based matching predicate
DEBUG(format("resolveWithin(cntnr=%s, name=%s) entering with predicate", currentContainer, name));
return resolveWithin(currentContainer, derive_nameMatch(name));
}
public void collectWithin(Container currentContainer, Predicate!(Statement) pred, ref Statement[] collection)
{
Statement[] statements = currentContainer.getStatements();
foreach(Statement statement; statements)
{
if(pred(statement))
{
collection ~= statement;
}
}
}
public void collectUpwards(Container currentContainer, Predicate!(Statement) pred, ref Statement[] collected)
{
// Collect everything at the current level
collectWithin(currentContainer, pred, collected);
// If the current container a Statement
if(cast(Statement)currentContainer)
{
Statement cntnrStmt = cast(Statement)currentContainer;
if(pred(cntnrStmt))
{
collected ~= cntnrStmt;
}
// Does it have a parent?
Container parent = cntnrStmt.parentOf();
if(parent)
{
collectUpwards(parent, pred, collected);
}
}
}
/**
* Performs a horizontal-based search of the given
* `Container`, returning the first `Entity` found
* when a positive verdict is returned from having
* the provided predicate applied to it.
*
* If the verdict is `false` then we do not give
* up immediately but rather recurse up the parental
* tree searching the container of the current
* container and applying the same logic.
*
* The stopping condition is when the current
* container has no ancestral parent, then
* we return `null`.
*
* Params:
* currentContainer = the starting container
* to begin the search from
* predicate = the predicate to apply
* Returns: an `Entity` or `null`
*/
public Entity resolveUp(Container currentContainer, Predicate!(Entity) predicate)
{
/* Try to find the Entity within the current Container */
DEBUG
(
format
(
"resolveUp(c=%s, pred=%s)",
currentContainer,
predicate
)
);
Entity entity = resolveWithin(currentContainer, predicate);
DEBUG
(
format
(
"resolveUp(c=%s, pred=%s) within-search returned '%s'",
currentContainer,
predicate,
entity
)
);
/* If we found it return it */
if(entity)
{
return entity;
}
/**
* If nothing was found (and current container is `Program`)
* then there is no further up we can go and we must end the
* search with no result
*/
else if(cast(Program)currentContainer)
{
DEBUG
(
format
(
"resolveUp(cntr=%s, pred=%s) Entity was not found and we cannot crawl any further up as we are at the Program container now",
currentContainer,
predicate
)
);
return null;
}
/* If we didn't then try go up a container */
else
{
/**
* We will ONLY ever have a `Container`
* here of which is ALSO an `Entity`.
*/
assert(cast(Entity)currentContainer);
Container possibleParent = (cast(Entity) currentContainer).parentOf();
DEBUG
(
format
(
"resolveUp(c=%s, pred=%s) cur container typeid: %s",
currentContainer,
predicate,
currentContainer
)
);
DEBUG
(
format
(
"resolveUp(c=%s, pred=%s) possible parent: %s",
currentContainer,
predicate,
possibleParent
)
);
/* Can we go up */
if(possibleParent)
{
return resolveUp(possibleParent, predicate);
}
/* If the current container has no parent container */
else
{
DEBUG
(
format
(
"resolveUp(c=%s, pred=%s) Simply not found ",
currentContainer,
predicate
)
);
return null;
}
}
}
/**
* Performs a horizontal-based search of the given
* `Container`, returning the first `Entity` found
* when such ne is found with a name matching the
* one provided
*
* If not found within the given container then we
* do not give up immediately but rather recurse
* up the parental tree searching the container
* of the current container and applying the same logic.
*
* The stopping condition is when the current
* container has no ancestral parent, then
* we return `null`.
*
* Params:
* currentContainer = the starting container
* to begin the search from
* name = the name of the `Entity` to search
* for
* Returns: an `Entity` or `null`
*/
public Entity resolveUp(Container currentContainer, string name)
{
return resolveUp(currentContainer, derive_nameMatch(name));
}
unittest
{
string input = "hello.world";
string[] path = split(input, '.');
assert(path.length == 2);
}
unittest
{
string input = "hello.";
string[] path = split(input, '.');
assert(path.length == 2);
}
unittest
{
string input = "hello";
string[] path = split(input, '.');
assert(path.length == 1);
}
unittest
{
string input = "";
string[] path = split(input, '.');
assert(path.length == 0);
}
/**
* This will do a best effort search starting
* for an entity with the given name. The search
* will start from the given container and
* perform a search within it, in the case no
* such entity is found there then it will
* recurse upwards, stopping when you reach
* the program-level.
*
* This also handles special cases such as
* dotted-paths, it can decode them and follow
* the trail to the intended entity.
*
* In the case that the container given
* is a `Program` then each name must
* either be solely a module name or
* a dotted-path beginning with one. In
* this mode nothing else is accepted,
* it effectively an absolute downwards
* (rather than potentially upwards
* search).
*
* Params:
* c = the starting container
* name = the name
* Returns: an `Entity` if found, otherwise
* `null`
*/
public Entity resolveBest(Container c, string name)
{
DEBUG
(
format
(
"resolveBest(cntnr=%s, name=%s) Entered",
c,
name
)
);
string[] path = split(name, '.');
assert(path.length); // We must have _something_ here
// Infact this should probably only be
// ...called relative to a Module, there
// are only some cases where it makes sense
// otherwise
if(cast(Program)c)
{
DEBUG
(
format
(
"resolveBest: Container is program (%s)",
c
)
);
Program programC = cast(Program)c;
// If you were asking just for the module
// e.g. `simple_module`
//
// Note that this won't consider doing
// a find of the entity in any other module
// if the path = ['g']. The reason for that is
// because a search rooted at the `Program`
// could find such an entity in ANY of the
// modules if we added such support but that
// would be kind of useless
if(path.length == 1)
{
string moduleRequested = name;
foreach(Module curMod; programC.getModules())
{
DEBUG
(
format
(
"resolveBest(moduleHorizontal): %s",
curMod
)
);
if(cmp(moduleRequested, curMod.getName()) == 0)
{
return curMod;
}
}
ERROR
(
"resolveBest(moduleHoritontal) We found nothing and will not go down from Program to any Module[]. You probably did a rooted search on the Program for a bnon-Module entity, didn't ya?"
);
return null;
}
// If you were asking for some entity
// anchored within a module
// e.g.`simple_module.x`
else
{
// First ensure a valid module name as anchor
string moduleRequested = path[0];
Container anchor;
foreach(Module curMod; programC.getModules())
{
DEBUG
(
format
(
"resolveBest(moduleHorizontal): %s",
curMod
)
);
if(cmp(moduleRequested, curMod.getName()) == 0)
{
anchor = curMod;
break;
}
}
// If we found the module
// then do an anchored search
// on the remaining path
if(anchor)
{
string remainingPath = join(path[1..$], ".");
return resolveBest(anchor, remainingPath);
}
// If we could not find the module
else
{
ERROR
(
format
(
"resolveBest(Program root): Could not find module '%s' for ANCHORED access",
moduleRequested
)
);
return null;
}
}
}
/**
* All objects that implement Container so far
* are also Entities (hence they have a name).
*
* The above is ONLY true except when you
* have a `Program` BUT we handle the case
* whereby `c` is a `Program` above, hence
* meaning that this code is unreachable in
* such a case and therefore safe.
*/
Entity containerEntity = cast(Entity) c;
assert(containerEntity);
DEBUG
(
format
(
"resolveBest(cntr=%s,name=%s) path = %s",
c,
name,
path
)
);
/**
* If no dot
*
* Try and find `name` within c
*/
if (path.length == 1)
{
/**
* Check if the name, regardless of container,
* matches any of the roots (modules attached
* to this program)
*/
foreach(Module curModule; this.program.getModules())
{
if(cmp(name, curModule.getName()) == 0)
{
return curModule;
}
}
Entity entityWithin = resolveUp(c, name);
/* If `name` was in container `c` or above it */
if (entityWithin)
{
return entityWithin;
}
/* If `name` was NOT found within container `c` or above it */
else
{
return null;
}
}
else
{
/* If the root is the current container */
if (cmp(path[0], containerEntity.getName()) == 0)
{
/* If only 1 left then just grab it */
if (path.length == 2)
{
Entity entityNext = resolveWithin(c, path[1]);
return entityNext;
}
/* Go deeper */
else
{
string newPath = name[indexOf(name, '.') + 1 .. name.length];
Entity entityNext = resolveWithin(c, path[1]);
/* If null then not found */
if (entityNext)
{
Container containerWithin = cast(Container) entityNext;
if (entityNext)
{
return resolveBest(containerWithin, newPath);
}
else
{
return null;
}
}
else
{
return null;
}
}
}
/* We need to search higher */
else
{
/**
* Check if the name is of one of the modules
* attached to the program
*/
foreach(Module curModule; this.program.getModules())
{
if(cmp(curModule.getName(), path[0]) == 0)
{
DEBUG
(
format
(
"About to search for name='%s' in module %s",
name,
curModule
)
);
return resolveBest(curModule, name);
}
}
Entity entityFound = resolveUp(c, path[0]);
if (entityFound)
{
Container con = cast(Container) entityFound;
if (con)
{
DEBUG("fooook");
return resolveBest(con, name);
}
else
{
DEBUG("also a kill me");
return null;
}
}
else
{
DEBUG("killl me");
return null;
}
}
}
}
/**
* Given a type-of `Container` and a starting `Statement` (AST node) this will
* swim upwards to try and find the first matching parent of which is of the given
* type (exactly, not kind-of).
*
* Params:
* containerType = the type-of `Container` to look for
* startingNode = the starting AST node (as a `Statement`)
* Returns: the found `Container`, or `null` if not found
*/
public Container findContainerOfType(TypeInfo_Class containerType, Statement startingNode)
{
DEBUG
(
format
(
"findContainerOfType(TypeInfo_Class, Statement): StmtStart: %s",
startingNode
)
);
DEBUG
(
format
(
"findContainerOfType(TypeInfo_Class, Statement): StmtStart (type): %s",
startingNode.classinfo
)
);
// If the given AST object is null, return null
if(startingNode is null)
{
return null;
}
// If the given AST object's type is of the type given
else if(typeid(startingNode) == containerType)
{
// Sanity check: You should not be calling
// with a TypeInfo_Class referring to a non-`Container`
assert(cast(Container)startingNode);
return cast(Container)startingNode;
}
// If not, swim up to the parent
else
{
DEBUG
(
format
(
"parent of %s is %s",
startingNode,
startingNode.parentOf()
)
);
return findContainerOfType(containerType, cast(Statement)startingNode.parentOf());
}
}
}
version(unittest)
{
import std.file;
import std.stdio;
import tlang.compiler.lexer.core;
import tlang.compiler.lexer.kinds.basic : BasicLexer;
import tlang.compiler.typecheck.core;
import tlang.misc.exceptions : TError;
}
/**
* Tests out various parts of the
* `Resolver`
*/
unittest
{
string sourceCode = `
module resolution_test_1;
int g;
`;
File dummyFile;
Compiler compiler = new Compiler(sourceCode, "legitidk.t", dummyFile);
try
{
compiler.doLex();
assert(true);
}
catch(LexerException e)
{
assert(false);
}
try
{
compiler.doParse();
Program program = compiler.getProgram();
// There is only a single module in this program
Module modulle = program.getModules()[0];
/* Module name must be resolution_test_1 */
assert(cmp(modulle.getName(), "resolution_test_1")==0);
TypeChecker tc = new TypeChecker(compiler);
// Now try to find the variable `d` by starting at the program-level
// this SHOULD fail as it should NOT be allowed
Entity var = tc.getResolver().resolveBest(program, "g");
assert(var is null);
// Try to find the variable `d` by starting at the module-level
var = tc.getResolver().resolveBest(modulle, "g");
assert(var);
assert(cast(Variable)var); // Ensure it is a variable
// We should be able to do a rooted search for a module, however,
// at the Program level
Entity myModule = tc.getResolver().resolveBest(program, "resolution_test_1");
assert(myModule);
assert(cast(Module)myModule); // Ensure it is a Module
// The `g` should be a descendant of the module and the module of the program
assert(tc.getResolver().isDescendant(cast(Container)myModule, var));
assert(tc.getResolver().isDescendant(cast(Container)program, myModule));
// Lookup `resolution_test_1.g` but anchored from the `Program`
Entity varAgain = tc.getResolver().resolveBest(program, "resolution_test_1.g");
assert(varAgain);
assert(cast(Variable)varAgain); // Ensure it is a Variable
// Generate the name from the program as the anchor
string nameFromProgram = tc.getResolver().generateName(program, var);
DEBUG(format("nameFromProgram: %s", nameFromProgram));
assert(nameFromProgram == "resolution_test_1.g");
// Generate the name from the module as the anchor (should be same as above)
string nameFromModule = tc.getResolver().generateName(cast(Container)myModule, var);
DEBUG(format("nameFromModule: %s", nameFromModule));
assert(nameFromModule == "resolution_test_1.g");
// Generate absolute path of the entity WITHOUT an anchor point
string bestName = tc.getResolver().generateNameBest(var);
DEBUG(format("bestName: %s", bestName));
assert(bestName == "resolution_test_1.g");
}
catch(TError e)
{
assert(false);
}
}