added compilation to assembly (binary is still weird)
This commit is contained in:
139
src/parse.ml
139
src/parse.ml
@@ -1,29 +1,134 @@
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let parse stm g =
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let s = (Token.new_scanner stm) in
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try
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Token.program s g
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with End_of_file ->
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Token.syntax_error s "program reached end of file before end keyword"
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let add s g d l r =
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match (l, r) with
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| (Token.Literal l1,Token.Literal l2) ->Token.Literal (l1+l2)
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| (Token.Identifier _, Token.Literal _) -> Codegen.generate_add s g d l r
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| (Token.Literal _, Token.Identifier _) -> Codegen.generate_add s g d r l
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| _ -> Token.syntax_error s "expected literal or identifier for add operation"
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let program s g =
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if Token.match_token s Token.Begin then
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let _ = generate_begin s g in
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let _ = statements s g in
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if Token.match_token s Token.End then
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let _ = generate_end s g in ()
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else Token.syntax_error s "program should end with end keyword"
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else Token.syntax_error s "program should start with begin keyword"
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let sub s g d l r =
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match (l, r) with
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| (Token.Literal l1,Token.Literal l2) ->Token.Literal (l1-l2)
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| (Token.Identifier _, Token.Literal _) -> Codegen.generate_sub s g d l r
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| (Token.Literal _, Token.Identifier _) -> Codegen.generate_sub s g d l r
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| _ -> Token.syntax_error s "expected literal or identifier for sub operation"
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let rec statements s g = if statement s g then statements s g else ()
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let rec expression s g d =
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let primary s =
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match Token.next_token s with
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| Token.LeftParen ->
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let _ = Token.match_token s Token.LeftParen in
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let e = expression s g (d+1) in
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if Token.match_token s Token.RightParen
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then Some e
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else Token.syntax_error s "right paren expected in expression"
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| Token.Identifier i ->
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let _ = Token.match_token s (Token.Identifier i) in
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Some (Token.Identifier i)
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| Token.Literal l ->
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let _ = Token.match_token s (Token.Literal l) in
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Some (Token.Literal l)
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| _ -> None
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in
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let lp = primary s in
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match lp with
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| Some l ->
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(match Token.next_token s with
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| Token.Add ->
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let _ = Token.match_token s Add in
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add s g d l (expression s g (d+1))
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| Token.Sub ->
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let _ = Token.match_token s Sub in
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sub s g d l (expression s g (d+1))
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| _ -> l)
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| None -> Token.syntax_error s "literal or identifier expected"
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let write s g =
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let rec expressions c =
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let e = expression s g 1 in
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if match e with
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| Token.Identifier _ -> let _ = Codegen.generate_write s g e in true
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| Token.Literal _ -> let _ = Codegen.generate_write s g e in true
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| _ -> false
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then if (Token.next_token s) = Token.Comma
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then let _ = Token.match_token s Token.Comma in expressions (c+1)
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else (c+1)
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else c
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in
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if Token.match_token s Token.Write then
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if Token.match_token s Token.LeftParen then
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if expressions 0 > 0 then
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if Token.match_token s Token.RightParen then true
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else Token.syntax_error s "right paren expected in write statement"
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else Token.syntax_error s "write statement expects at least one expression"
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else Token.syntax_error s "left paren expected in write statement"
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else Token.syntax_error s "write statement expected"
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let identifiers s =
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let rec idens ids =
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match Token.next_token s with
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| Token.Identifier i ->
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let _ = Token.match_next s in
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let n = Token.next_token s in
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if n = Token.Comma
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then let _ = Token.match_token s Token.Comma in idens (Token.Identifier i :: ids)
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else idens (Token.Identifier i :: ids)
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| _ -> ids
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in idens []
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let read s g =
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if Token.match_token s Token.Read then
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if Token.match_token s Token.LeftParen then
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let ids = identifiers s in
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if ids = []
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then Token.syntax_error s "read statement expects comma seperated identifier(s)"
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else if Token.match_token s Token.RightParen
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then let _ = Codegen.generate_reads s g (List.rev ids) in true
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else Token.syntax_error s "right paren expected in read statement"
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else Token.syntax_error s "left paren expected in read statement"
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else Token.syntax_error s "read statement expected"
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let assignment s g =
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let id = Token.match_next s in
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match id with
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Token.Identifier i ->
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if Token.match_token s Token.Assign
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then
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let new_var = if Codegen.is_alloc_var s g i then 0 else 1 in
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let id2 = expression s g (1+new_var) in
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match id2 with
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| Token.Literal _ ->
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let _ = Codegen.generate_assign s g id id2 in true
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| Token.Identifier _ ->
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let _ = Codegen.generate_assign s g id id2 in true
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| _ -> Token.syntax_error s "literal or identifier expected"
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else Token.syntax_error s "assign symbol expected"
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| _ -> Token.syntax_error s "identifier expected"
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let statement s g =
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let t = next_token s in
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let t = Token.next_token s in
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if match t with
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| Token.Read -> read s g
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| Token.Write -> write s g
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| Token.Identifier i -> assignment s g
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| Token.Identifier _ -> assignment s g
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| _ -> false
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then
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if Token.match_token s Token.Semicolon then true
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else Token.syntax_error s "statement must end with semicolon"
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else false
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let rec statements s g = if statement s g then statements s g else ()
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let program s g =
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if Token.match_token s Token.Begin then
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let _ = Codegen.generate_begin s g in
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let _ = statements s g in
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if Token.match_token s Token.End then
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let _ = Codegen.generate_end s g in ()
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else Token.syntax_error s "program should end with end keyword"
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else Token.syntax_error s "program should start with begin keyword"
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let parse stm g =
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let s = (Token.new_scanner stm) in
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try program s g
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with End_of_file ->
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Token.syntax_error s "program reached end of file before end keyword"
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