nocturn9x
/
peon
2
2
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Added switch statements

This commit is contained in:
Mattia Giambirtone 2022-12-07 09:15:29 +01:00
parent af3c7234be
commit f1875736e3
8 changed files with 109 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/backend/vm.nim
View File

@ -851,6 +851,8 @@ proc dispatch*(self: var PeonVM) =
# Pops N elements off the call stack
for _ in 0..<int(self.readShort()):
discard self.popc()
of DupTop:
self.push(self.peek())
# Jump opcodes
of Jump:
# Absolute jump

22
src/frontend/compiler.nim
View File

@ -2629,6 +2629,26 @@ proc namedBlock(self: Compiler, node: NamedBlockStmt) =
self.endScope()
proc switchStmt(self: Compiler, node: SwitchStmt) =
## Compiles switch statements
self.expression(node.switch)
var ifJump: int = -1
var thenJumps: seq[int] = @[]
for branch in node.branches:
self.emitByte(DupTop, branch.body.token.line)
self.expression(branch.cond)
self.emitByte(Equal, branch.body.token.line)
ifJump = self.emitJump(JumpIfFalsePop, branch.body.token.line)
self.blockStmt(branch.body)
thenJumps.add(self.emitJump(JumpForwards, branch.body.token.line))
self.patchJump(ifJump)
if not node.default.isNil():
self.blockStmt(node.default)
for jump in thenJumps:
self.patchJump(jump)
self.emitByte(OpCode.Pop, node.token.line)
proc statement(self: Compiler, node: Statement) =
## Compiles all statements
case node.kind:
@ -2644,6 +2664,8 @@ proc statement(self: Compiler, node: Statement) =
self.printRepl(kind, expression)
else:
self.emitByte(Pop, node.token.line)
of NodeKind.switchStmt:
self.switchStmt(SwitchStmt(node))
of NodeKind.namedBlockStmt:
self.namedBlocks.add(NamedBlock(start: self.chunk.code.len(),
depth: self.depth,

17
src/frontend/meta/ast.nim
View File

@ -77,7 +77,8 @@ type
identExpr, # Identifier
pragmaExpr,
refExpr,
ptrExpr
ptrExpr,
switchStmt
# Here I would've rather used object variants, and in fact that's what was in
# place before, but not being able to re-declare a field of the same type in
@ -291,6 +292,11 @@ type
Ptr* = ref object of Expression
value*: Expression
SwitchStmt* = ref object of Statement
switch*: Expression
branches*: seq[tuple[cond: Expression, body: BlockStmt]]
default*: BlockStmt
proc isConst*(self: ASTNode): bool =
@ -337,6 +343,15 @@ proc newPtrExpr*(expression: Expression, token: Token): Ptr =
result.token = token
proc newSwitchStmt*(switch: Expression, branches: seq[tuple[cond: Expression, body: BlockStmt]], default: BlockStmt, token: Token): SwitchStmt =
new(result)
result.kind = switchStmt
result.switch = switch
result.branches = branches
result.token = token
result.default = default
proc newIntExpr*(literal: Token): IntExpr =
result = IntExpr(kind: intExpr)
result.literal = literal

4
src/frontend/meta/bytecode.nim
View File

@ -186,7 +186,8 @@ type
PopC, # Pop off the call stack onto the operand stack
PushC, # Pop off the operand stack onto the call stack
SysClock64, # Pushes the output of a monotonic clock on the stack
LoadTOS # Pushes the top of the call stack onto the operand stack
LoadTOS, # Pushes the top of the call stack onto the operand stack
DupTop # Duplicates the top of the operand stack onto the operand stack
# We group instructions by their operation/operand types for easier handling when debugging
@ -265,6 +266,7 @@ const simpleInstructions* = {Return, LoadNil,
Float32LessThan,
Float32GreaterOrEqual,
Float32LessOrEqual,
DupTop
}
# Constant instructions are instructions that operate on the bytecode constant table

2
src/frontend/meta/token.nim
View File

@ -38,7 +38,7 @@ type
Yield, Defer, Try, Except,
Finally, Type, Operator, Case,
Enum, From, Ptr, Ref, Object,
Export, Block, Template
Export, Block, Template, Switch,
# Literal types
Integer, Float, String, Identifier,

25
src/frontend/parser.nim
View File

@ -1203,12 +1203,37 @@ proc expressionStatement(self: Parser): Statement =
result.file = self.file
proc switchStmt(self: Parser): Statement =
## Parses switch statements
let tok = self.peek(-1)
let switch = self.expression()
self.expect(TokenType.LeftBrace, "expecting '{' after switch condition")
var branches: seq[tuple[cond: Expression, body: BlockStmt]] = @[]
var match: Expression
var body: BlockStmt
var default: BlockStmt
while not self.check([TokenType.RightBrace, TokenType.Else]) and not self.done():
self.expect(TokenType.Case, "expecting at least one 'case' label in switch statement")
match = self.expression()
self.expect(TokenType.LeftBrace, "expecting '{' after expression match in switch statement")
body = BlockStmt(self.blockStmt())
branches.add((cond: match, body: body))
if self.match(Else):
self.expect(TokenType.LeftBrace, "expecting '{' after else clause in switch statement")
default = BlockStmt(self.blockStmt())
self.expect(TokenType.RightBrace, "missing closing '}' in switch statement")
result = newSwitchStmt(switch, branches, default, tok)
proc statement(self: Parser): Statement =
## Parses statements
case self.peek().kind:
of If:
discard self.step()
result = self.ifStmt()
of Switch:
discard self.step()
result = self.switchStmt()
of Assert:
discard self.step()
result = self.assertStmt()

5
src/util/symbols.nim
View File

@ -46,6 +46,9 @@ proc fillSymbolTable*(tokenizer: Lexer) =
tokenizer.symbols.addKeyword("return", TokenType.Return)
tokenizer.symbols.addKeyword("object", Object)
tokenizer.symbols.addKeyword("export", Export)
tokenizer.symbols.addKeyword("block", TokenType.Block)
tokenizer.symbols.addKeyword("template", TokenType.Template)
tokenizer.symbols.addKeyword("switch", TokenType.Switch)
# These are more like expressions with a reserved
# name that produce a value of a builtin type,
# but we don't need to care about that until
@ -55,8 +58,6 @@ proc fillSymbolTable*(tokenizer: Lexer) =
tokenizer.symbols.addKeyword("false", False)
tokenizer.symbols.addKeyword("ref", TokenType.Ref)
tokenizer.symbols.addKeyword("ptr", TokenType.Ptr)
tokenizer.symbols.addKeyword("block", TokenType.Block)
tokenizer.symbols.addKeyword("template", TokenType.Template)
for sym in [">", "<", "=", "~", "/", "+", "-", "_", "*", "?", "@", ":", "==", "!=",
">=", "<=", "+=", "-=", "/=", "*=", "**=", "!", "%", "&", "|", "^",
">>", "<<"]:

37
tests/switch.pn Normal file
View File

@ -0,0 +1,37 @@
import std;
switch 2 + 2 {
case 4 {
print(true);
}
case 3 {
print(false);
}
else {
print(false);
}
}
switch 2 + 1 {
case 4 {
print(false);
}
case 3 {
print(true);
}
}
switch 2 + 3 {
case 4 {
print(false);
}
case 3 {
print(false);
}
else {
print(true);
}
}