fspl/analyzer/expression.go

784 lines
18 KiB
Go

package analyzer
import "fmt"
import "git.tebibyte.media/fspl/fspl/errors"
import "git.tebibyte.media/fspl/fspl/entity"
// All expression analysis routines must take in the type they are being
// assigned to and return an error if they can't be assigned to it. if the type
// is nil, the expression must ignore it unless it can do upwards type
// inference.
func (this *Tree) analyzeAssignment (
assignment *entity.Assignment,
) (
entity.Expression,
error,
) {
// analyze location
location, err := this.analyzeExpression(nil, strict, assignment.Location)
if err != nil { return nil, err }
assignment.Location = location
// ensure location is location expression
err = this.isLocationExpression(location)
if err != nil { return nil, err }
// analyze value
value, err := this.analyzeExpression(location.Type(), strict, assignment.Value)
if err != nil { return nil, err }
assignment.Value = value
return assignment, nil
}
func (this *Tree) analyzeVariable (
into entity.Type,
mode strictness,
variable *entity.Variable,
) (
entity.Expression,
error,
) {
declaration := this.variable(variable.Name)
if declaration == nil {
return nil, errors.Errorf (
variable.Position, "no variable named %s",
variable.Name)
}
err := this.canAssign(variable.Position, into, mode, declaration.Type())
if err != nil { return nil, err }
variable.Declaration = declaration
return variable, nil
}
func (this *Tree) analyzeDeclaration (
into entity.Type,
mode strictness,
declaration *entity.Declaration,
) (
entity.Expression,
error,
) {
scope, _ := this.topScope()
existing := scope.Variable(declaration.Name)
if existing != nil {
return nil, errors.Errorf (
declaration.Position,
"%s already declared in block at %v",
declaration.Name, existing.Position)
}
ty, err := this.analyzeType(declaration.Ty, false)
declaration.Ty = ty
if err != nil { return nil, err }
err = this.canAssign(declaration.Position, into, mode, declaration.Type())
if err != nil { return nil, err }
this.addVariable(declaration)
return declaration, nil
}
func (this *Tree) analyzeCall (
into entity.Type,
mode strictness,
call *entity.Call,
) (
entity.Expression,
error,
) {
// get function
unit, err := this.resolveNickname(call.Position, call.UnitNickname)
if err != nil { return nil, err }
function, err := this.analyzeFunction(call.Position, entity.Key {
Unit: unit,
Name: call.Name,
})
if err != nil { return nil, err }
call.Function = function
call.Unit = function.Unit
// check access permissions
if function.Acc == entity.AccessPrivate && function.Unit != this.unit {
return nil, errors.Errorf (
call.Position, "function %v::[%v] is private",
call.UnitNickname, call.Name)
}
// check return result
err = this.canAssign(call.Position, into, mode, function.Signature.Return)
if err != nil { return nil, err }
// check arg count
if len(call.Arguments) > len(function.Signature.Arguments) {
return nil, errors.Errorf (
call.Position, "too many arguments in call to %s",
call.Name)
} else if len(call.Arguments) < len(function.Signature.Arguments) {
return nil, errors.Errorf (
call.Position, "too few arguments in call to %s",
call.Name)
}
// check arg types
for index, argument := range call.Arguments {
signature := function.Signature
correct := signature.ArgumentMap[signature.ArgumentOrder[index]]
argument, err := this.analyzeExpression(correct.Type(), strict, argument)
if err != nil { return nil, err }
call.Arguments[index] = argument
}
return call, nil
}
func (this *Tree) analyzeMethodCall (
into entity.Type,
mode strictness,
call *entity.MethodCall,
) (
entity.Expression,
error,
) {
// get method
source, err := this.analyzeExpression(nil, strict, call.Source)
if err != nil { return nil, err }
method, err := this.analyzeMethodOrBehavior (
call.Position, source.Type(), call.Name)
if err != nil { return nil, err }
// extract signature
var signature *entity.Signature
switch method := method.(type) {
case *entity.Signature:
signature = method
call.Behavior = signature
// since this is a behavior, check access permissions of the
// interface
err = this.typeRestricted(call.Position, source.Type())
if err != nil { return nil, err }
case *entity.Method:
signature = method.Signature
call.Method = method
// since this is a method, check access permissions of the
// method
if method.Acc == entity.AccessPrivate && method.Unit != this.unit {
return nil, errors.Errorf (
call.Position, "method %v.[%v] is private",
method.TypeName, method.Signature.Name)
}
default:
panic(fmt.Sprint (
"Tree.analyzeMethodOrBehavior returned ",
method))
}
// check return result
err = this.canAssign(call.Position, into, mode, signature.Return)
if err != nil { return nil, err }
// check arg count
if len(call.Arguments) > len(signature.Arguments) {
return nil, errors.Errorf (
call.Position, "too many arguments in call to %s",
call.Name)
} else if len(call.Arguments) < len(signature.Arguments) {
return nil, errors.Errorf (
call.Position, "too few arguments in call to %s",
call.Name)
}
// check arg types
for index, argument := range call.Arguments {
correct := signature.ArgumentMap[signature.ArgumentOrder[index]]
argument, err := this.analyzeExpression(correct.Type(), strict, argument)
if err != nil { return nil, err }
call.Arguments[index] = argument
}
return call, nil
}
func (this *Tree) analyzeSubscript (
into entity.Type,
mode strictness,
subscript *entity.Subscript,
) (
entity.Expression,
error,
) {
slice, err := this.analyzeExpression (
&entity.TypeSlice {
Position: subscript.Position,
Element: into,
}, weak,
subscript.Slice)
if err != nil { return nil, err }
subscript.Slice = slice
subscript.Ty = into
// check permissions
err = this.typeRestricted(subscript.Position, slice.Type())
if err != nil { return nil, err }
offset, err := this.analyzeExpression (
builtinType("Index"), weak,
subscript.Offset)
if err != nil { return nil, err }
subscript.Offset = offset
var frailType bool
switch into := into.(type) {
case nil: frailType = true
case *entity.TypeSlice: frailType = into.Element == nil
}
if frailType {
ty := ReduceToBase(subscript.Slice.Type())
switch ty := ty.(type) {
case *entity.TypeSlice: subscript.Ty = ty.Element
case *entity.TypeArray: subscript.Ty = ty.Element
}
}
return subscript, nil
}
func (this *Tree) analyzeSlice (
into entity.Type,
mode strictness,
slice *entity.Slice,
) (
entity.Expression,
error,
) {
value, err := this.analyzeExpression(into, weak, slice.Slice)
if err != nil { return nil, err }
slice.Slice = value
// check permissions
err = this.typeRestricted(slice.Position, value.Type())
if err != nil { return nil, err }
if slice.Start != nil {
start, err := this.analyzeExpression (
builtinType("Index"), weak,
slice.Start)
if err != nil { return nil, err }
slice.Start = start
}
if slice.End != nil {
end, err := this.analyzeExpression (
builtinType("Index"), weak,
slice.End)
if err != nil { return nil, err }
slice.End = end
}
return slice, nil
}
func (this *Tree) analyzeLength (
into entity.Type,
mode strictness,
length *entity.Length,
) (
entity.Expression,
error,
) {
value, err := this.analyzeExpression(nil, strict, length.Slice)
if err != nil { return nil, err }
length.Slice = value
length.Ty = builtinType("Index")
return length, nil
}
func (this *Tree) analyzeDereference (
into entity.Type,
mode strictness,
dereference *entity.Dereference,
) (
entity.Expression,
error,
) {
pointer, err := this.analyzeExpression (
&entity.TypePointer {
Position: dereference.Position,
Referenced: into,
}, weak,
dereference.Pointer)
if err != nil { return nil, err }
dereference.Pointer = pointer
dereference.Ty = into
var frailType bool
switch into := into.(type) {
case nil: frailType = true
case *entity.TypePointer: frailType = into.Referenced == nil
}
if frailType {
ty := ReduceToBase(dereference.Pointer.Type())
switch ty := ty.(type) {
case *entity.TypePointer: dereference.Ty = ty.Referenced
}
}
return dereference, nil
}
func (this *Tree) analyzeReference (
into entity.Type,
mode strictness,
reference *entity.Reference,
) (
entity.Expression,
error,
) {
referenced, ok := into.(*entity.TypePointer)
if !ok {
return nil, errors.Errorf(reference.Position, "expected %v", into)
}
value, err := this.analyzeExpression (
referenced.Referenced, weak,
reference.Value)
if err != nil { return nil, err }
err = this.isLocationExpression(reference.Value)
if err != nil { return nil, err }
reference.Value = value
reference.Ty = referenced.Referenced
return reference, nil
}
func (this *Tree) analyzeValueCast (
into entity.Type,
mode strictness,
cast *entity.ValueCast,
) (
entity.Expression,
error,
) {
ty, err := this.analyzeType(cast.Ty, false)
if err != nil { return nil, err }
cast.Ty = ty
err = this.canAssign(cast.Position, into, mode, cast.Type())
if err != nil { return nil, err }
value, err := this.analyzeExpression(cast.Ty, coerce, cast.Value)
if err != nil { return nil, err }
cast.Value = value
return cast, nil
}
func (this *Tree) analyzeBitCast (
into entity.Type,
mode strictness,
cast *entity.BitCast,
) (
entity.Expression,
error,
) {
ty, err := this.analyzeType(cast.Ty, false)
if err != nil { return nil, err }
cast.Ty = ty
err = this.canAssign(cast.Position, into, mode, cast.Type())
if err != nil { return nil, err }
value, err := this.analyzeExpression(cast.Ty, force, cast.Value)
if err != nil { return nil, err }
cast.Value = value
return cast, nil
}
func (this *Tree) analyzeOperation (
into entity.Type,
mode strictness,
operation *entity.Operation,
) (
entity.Expression,
error,
) {
// check permissions
err := this.typeRestricted(operation.Position, into)
if err != nil { return nil, err }
wrongInto := func () (entity.Expression, error) {
return nil, errors.Errorf (
operation.Position, "expected %v",
entity.FormatType(into))
}
wrongArgCount := func () (entity.Expression, error) {
return nil, errors.Errorf (
operation.Position, "wrong argument count for %v",
operation.Operator)
}
nSameType := func (n int, constraint func (entity.Type) bool) (entity.Expression, error) {
if n > 0 {
if len(operation.Arguments) != n { return wrongArgCount() }
} else {
if len(operation.Arguments) < 1 { return wrongArgCount() }
}
n = len(operation.Arguments)
if !constraint(into) { return wrongInto() }
left, err := this.analyzeExpression(into, mode, operation.Arguments[0])
if err != nil { return nil, err }
operation.Arguments[0] = left
operation.Ty = left.Type()
for index := 1; index < n; index ++ {
argument, err := this.analyzeExpression (
left.Type(), strict,
operation.Arguments[index])
if err != nil { return nil, err }
operation.Arguments[index] = argument
}
return operation, nil
}
comparison := func (argConstraint func (entity.Type) bool) (entity.Expression, error) {
if len(operation.Arguments) < 2 { return wrongArgCount() }
if !isBoolean(into) { return wrongInto() }
operation.Ty = builtinType("Bool")
// find the first argument that has explicit type information.
// TODO: possibly make a method of expressions to check this
// without analyzing anything
boss := -1
var argumentType entity.Type
for index, argument := range operation.Arguments {
argument, err := this.analyzeExpression(nil, strict, argument)
if err == nil {
boss = index
operation.Arguments[index] = argument
argumentType = argument.Type()
break
}
}
if argumentType == nil {
return nil, errors.Errorf (
operation.Position,
"operation arguments have ambiguous type")
}
// analyze all remaining arguments
for index, argument := range operation.Arguments {
if index == boss { continue }
argument, err := this.analyzeExpression (
argumentType, strict, argument)
if err != nil {
boss = index
operation.Arguments[index] = argument
break
}
operation.Arguments[index] = argument
}
return operation, nil
}
switch operation.Operator {
// math
case entity.OperatorAdd,
entity.OperatorSubtract,
entity.OperatorMultiply,
entity.OperatorDivide,
entity.OperatorIncrement,
entity.OperatorDecrement:
return nSameType(-1, isNumeric)
case entity.OperatorModulo:
return nSameType(2, isNumeric)
// logic
case entity.OperatorLogicalNot:
return nSameType(1, isBoolean)
case entity.OperatorLogicalOr,
entity.OperatorLogicalAnd,
entity.OperatorLogicalXor:
return nSameType(-1, isBoolean)
// bit manipulation
case entity.OperatorNot:
return nSameType(1, isInteger)
case entity.OperatorOr, entity.OperatorAnd, entity.OperatorXor:
return nSameType(-1, isInteger)
case entity.OperatorLeftShift, entity.OperatorRightShift:
if len(operation.Arguments) != 2 { return wrongArgCount() }
if !isInteger(into) { return wrongInto() }
arg, err := this.analyzeExpression(into, mode, operation.Arguments[0])
if err != nil { return nil, err }
operation.Arguments[0] = arg
operation.Ty = arg.Type()
offset, err := this.analyzeExpression (
builtinType("Index"), weak,
operation.Arguments[1])
if err != nil { return nil, err }
operation.Arguments[1] = offset
return operation, nil
// comparison
case entity.OperatorLess,
entity.OperatorGreater,
entity.OperatorLessEqual,
entity.OperatorGreaterEqual:
return comparison(isOrdered)
case entity.OperatorEqual:
return comparison(isOrdered)
default:
panic(fmt.Sprint (
"BUG: analyzer doesnt know about operator ",
operation.Operator))
}
}
func (this *Tree) analyzeBlock (
into entity.Type,
mode strictness,
block *entity.Block,
) (
entity.Expression,
error,
) {
this.pushScope(block)
defer this.popScope()
if len(block.Steps) == 0 && into != nil {
return nil, errors.Errorf (
block.Position, "block must have at least one statement")
}
final := len(block.Steps) - 1
for index, step := range block.Steps {
if index == final && into != nil {
expression, ok := step.(entity.Expression)
if !ok {
return nil, errors.Errorf (
block.Position, "expected expression")
}
step, err := this.analyzeExpression(into, strict, expression)
if err != nil { return nil, err }
block.Steps[index] = step
block.Ty = step.Type()
} else {
step, err := this.analyzeExpression(nil, strict, step)
if err != nil { return nil, err }
block.Steps[index] = step
}
}
return block, nil
}
func (this *Tree) analyzeMemberAccess (
into entity.Type,
mode strictness,
access *entity.MemberAccess,
) (
entity.Expression,
error,
) {
source, err := this.analyzeExpression(nil, strict, access.Source)
if err != nil { return nil, err }
// determine type with the members
var sourceType *entity.TypeStruct
var qualifiedSourceType entity.Type
switch sourceTypeAny := ReduceToBase(source.Type()).(type) {
case *entity.TypeStruct:
sourceType = sourceTypeAny
qualifiedSourceType = source.Type()
case *entity.TypePointer:
referenced, ok := ReduceToBase(sourceTypeAny.Referenced).(*entity.TypeStruct)
if !ok {
return nil, errors.Errorf (
access.Position, "cannot access members of %v",
source)
}
sourceType = referenced
qualifiedSourceType = sourceTypeAny.Referenced
default:
return nil, errors.Errorf (
access.Position, "cannot access members of %v",
source)
}
// check permissions
err = this.typeRestricted(access.Position, qualifiedSourceType)
if err != nil { return nil, err }
// get member
member, ok := sourceType.MemberMap[access.Member]
if !ok {
return nil, errors.Errorf (
access.Position, "no member %v",
access)
}
err = this.canAssign(access.Position, into, mode, member.Type())
if err != nil { return nil, err }
access.Ty = member.Type()
return access, nil
}
func (this *Tree) analyzeIfElse (
into entity.Type,
mode strictness,
ifelse *entity.IfElse,
) (
entity.Expression,
error,
) {
condition, err := this.analyzeExpression (
&entity.TypeNamed {
Name: "Bool",
Type: builtinType("Bool"),
},
weak, ifelse.Condition)
if err != nil { return nil, err }
ifelse.Condition = condition
trueBranch, err := this.analyzeExpression(into, strict, ifelse.True)
if err != nil { return nil, err }
ifelse.True = trueBranch
if ifelse.False == nil {
if into != nil {
return nil, errors.Errorf (
ifelse.Position,
"else case required when using value of if ")
}
} else {
falseBranch, err := this.analyzeExpression(into, strict, ifelse.False)
if err != nil { return nil, err }
ifelse.False = falseBranch
}
ifelse.Ty = into
return ifelse, nil
}
func (this *Tree) analyzeLoop (
into entity.Type,
mode strictness,
loop *entity.Loop,
) (
entity.Expression,
error,
) {
loop.Ty = into
this.pushLoop(loop)
defer this.popLoop()
body, err := this.analyzeExpression(nil, strict, loop.Body)
if err != nil { return nil, err }
loop.Body = body
return loop, nil
}
func (this *Tree) analyzeBreak (
into entity.Type,
mode strictness,
brk *entity.Break,
) (
entity.Expression,
error,
) {
if into != nil {
return nil, errors.Errorf (
brk.Position, "expected %v",
entity.FormatType(into))
}
loop, ok := this.topLoop()
if !ok {
return nil, errors.Errorf (
brk.Position,
"break statement must be within loop")
}
brk.Loop = loop
if loop.Type() != nil && brk.Value == nil {
return nil, errors.Errorf (
brk.Position,
"break statement must have value")
}
if brk.Value != nil {
value, err := this.analyzeExpression(loop.Type(), strict, brk.Value)
if err != nil { return nil, err }
brk.Value = value
}
return brk, nil
}
func (this *Tree) analyzeReturn (
into entity.Type,
mode strictness,
ret *entity.Return,
) (
entity.Expression,
error,
) {
if into != nil {
return nil, errors.Errorf (
ret.Position, "expected %v",
entity.FormatType(into))
}
ret.Declaration, _ = this.topDeclaration()
var ty entity.Type
switch ret.Declaration.(type) {
case *entity.Function:
ty = ret.Declaration.(*entity.Function).Signature.Return
case *entity.Method:
ty = ret.Declaration.(*entity.Method).Signature.Return
}
if ty != nil && ret.Value == nil {
return nil, errors.Errorf (
ret.Position,
"break statement must have value")
}
if ret.Value != nil {
value, err := this.analyzeExpression(ty, strict, ret.Value)
if err != nil { return nil, err }
ret.Value = value
}
return ret, nil
}