Imperial-MEng/WACC_37
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fix: added error messages for functions missing type, and late function decls

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Barf-Vader
2025-02-07 01:35:16 +00:00
committed by Guy C
parent b3ecae5dbb
commit a65cc01815
2 changed files with 18 additions and 11 deletions
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22
src/main/wacc/parser.scala
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@@ -12,6 +12,8 @@ import cats.data.NonEmptyList
import parsley.errors.DefaultErrorBuilder
import parsley.errors.ErrorBuilder
import parsley.errors.tokenextractors.LexToken
import parsley.errors.patterns.VerifiedErrors
import parsley.character.char
object parser {
import lexer.implicits.implicitSymbol
@@ -48,6 +50,10 @@ object parser {
case Expr
case Pair
val _parensCheck =
char('(').verifiedExplain("use keyword 'call' to call functions")
implicit val builder: ErrorBuilder[String] = new DefaultErrorBuilder with LexToken {
def tokens = errTokens
}
@@ -66,8 +72,8 @@ object parser {
GreaterEq from ">="
) +:
SOps(InfixL)(
(Add from "+").label("binary operator"),
(Sub from "-").label("binary operator")
((Add from "+").label("binary operator") | _parensCheck),
((Sub from "-").label("binary operator") | _parensCheck)
) +:
SOps(InfixL)(Mul from "*", Div from "/", Mod from "%") +:
SOps(Prefix)(
@@ -117,15 +123,15 @@ object parser {
// Statements
private lazy val `<program>` = Program(
"begin" ~> many(
atomic(`<type>`.label("function declaration") <~> `<ident>` <~ "(") <**> `<partial-func-decl>`
atomic((`<type>`.label("function declaration") <~> `<ident>` <~ "(")) <**> `<partial-func-decl>`
).label("function declaration"),
`<stmt>`.label("main program body") <~ "end"
((`<ident>` <~ "(")*> fail("function is missing return type") | `<stmt>`.label("main program body")) <~ "end"
)
private lazy val `<partial-func-decl>` =
FuncDecl(
sepBy(`<param>`, ",") <~ ")" <~ "is",
sepBy(`<param>`, ",") <~ ")".label("parenthesis") <~ "is",
`<stmt>`.guardAgainst {
case stmts if !stmts.isReturning => Seq("All functions must end in a returning statement")
case stmts if !stmts.isReturning => Seq("all functions must end in a returning statement")
} <~ "end"
)
private lazy val `<param>` = Param(`<type>`, `<ident>`)
@@ -150,8 +156,8 @@ object parser {
)
| While("while" ~> `<expr>`.labelWithType(LabelType.Expr) <~ "do", `<stmt>` <~ "done")
| Block("begin" ~> `<stmt>` <~ "end")
| VarDecl(`<type>`, `<ident>` <~ "=", `<rvalue>`.label("valid initial value for variable"))
// TODO: Can we inline the name of the variable in the message
| VarDecl(`<type>`, `<ident>` <~ "=".explain("functions must be defined on top of the main block"),
`<rvalue>`.label("valid initial value for variable"))
| Assign(`<lvalue>` <~ "=", `<rvalue>`)
private lazy val `<lvalue>`: Parsley[LValue] =
`<pair-elem>` | `<ident-or-array-elem>`