parser.go.y

%{
package parser

import (
	"github.com/dgrr/pako/ast"
)

%}

%type<compstmt> compstmt
%type<modstmts> modstmts
%type<modstmt> modstmt
%type<stmts> stmts
%type<stmt> stmt
%type<stmt_var_or_lets> stmt_var_or_lets
%type<stmt_import> stmt_import
%type<stmt_module> stmt_module
%type<stmt_struct> stmt_struct
%type<stmt_var> stmt_var
%type<stmt_lets> stmt_lets
%type<stmt_if> stmt_if
%type<stmt_for> stmt_for
%type<stmt_switch> stmt_switch
%type<stmt_switch_cases> stmt_switch_cases
%type<stmt_switch_case> stmt_switch_case
%type<stmt_switch_default> stmt_switch_default

%type<exprs> exprs
%type<expr> expr
%type<expr_idents> expr_idents
%type<type_data> type_data
%type<type_data_struct> type_data_struct
%type<slice_count> slice_count
%type<expr_member_or_ident> expr_member_or_ident
%type<expr_member> expr_member
%type<expr_ident> expr_ident
%type<expr_literals> expr_literals
%type<expr_map> expr_map
%type<expr_slice> expr_slice
%type<expr_chan> expr_chan
%type<expr> expr_unary
%type<expr> expr_binary
%type<expr> expr_lets

%type<expr> op_binary
%type<expr> op_comparison
%type<expr> op_add
%type<expr> op_multiply

%union{
	tok                     ast.Token

	compstmt                ast.Stmt
	modstmts                ast.Stmt
	modstmt                 ast.Stmt
	stmts                   ast.Stmt
	stmt                    ast.Stmt
	stmt_var_or_lets        ast.Stmt
	stmt_import             ast.Stmt
	stmt_module             ast.Stmt
	stmt_struct             ast.Stmt
	stmt_var                ast.Stmt
	stmt_lets               ast.Stmt
	stmt_if                 ast.Stmt
	stmt_for                ast.Stmt
	stmt_switch             ast.Stmt
	stmt_switch_cases       ast.Stmt
	stmt_switch_case        ast.Stmt
	stmt_switch_default     ast.Stmt

	exprs                   []ast.Expr
	expr                    ast.Expr
	expr_idents             []string
	type_data               *ast.TypeStruct
	type_data_struct        *ast.TypeStruct
	slice_count             int
	expr_member_or_ident    ast.Expr
	expr_member             *ast.MemberExpr
	expr_ident              *ast.IdentExpr
	expr_literals           ast.Expr
	expr_map                *ast.MapExpr
	expr_slice              ast.Expr
	expr_chan               ast.Expr
	expr_unary              ast.Expr
	expr_binary             ast.Expr
	expr_lets               ast.Expr

	op_binary               ast.Operator
	op_comparison           ast.Operator
	op_add                  ast.Operator
	op_multiply             ast.Operator
}

%token<tok> IDENT NUMBER STRING ARRAY VARARG FUNC RETURN VAR THROW IF ELSE FOR IN EQEQ NEQ GE LE OROR ANDAND NEW TRUE FALSE NIL NILCOALESCE MODULE TRY CATCH FINALLY PLUSEQ MINUSEQ MULEQ DIVEQ ANDEQ OREQ BREAK CONTINUE PLUSPLUS MINUSMINUS SHIFTLEFT SHIFTRIGHT SWITCH CASE DEFAULT GO CHAN STRUCT MAKE OPCHAN EQOPCHAN TYPE LEN DELETE CLOSE MAP IMPORT AS

/* lowest precedence */
%left ,
%right '=' PLUSEQ MINUSEQ MULEQ DIVEQ ANDEQ OREQ EQOPCHAN
%right ':'
%right OPCHAN
%right '?' NILCOALESCE
%left OROR
%left ANDAND
%left EQEQ NEQ '<' LE '>' GE
%left '+' '-' '|' '^'
%left '*' '/' '%' SHIFTLEFT SHIFTRIGHT '&'
%right IN
%right PLUSPLUS MINUSMINUS
%right UNARY
/* highest precedence */
/* https://golang.org/ref/spec#Expression */

%%

compstmt :
	opt_term
	{
		$$ = nil
	}
	| stmts opt_term
	{
		$$ = $1
	}

stmts :
	opt_term stmt
	{
		if $2 != nil {
			$$ = &ast.StmtsStmt{Stmts: []ast.Stmt{$2}}
		}
		if l, ok := yylex.(*Lexer); ok {
			l.stmt = $$
		}
	}
	| stmts term stmt
	{
		if $3 != nil {
			if $1 == nil {
				$$ = &ast.StmtsStmt{Stmts: []ast.Stmt{$3}}
			} else {
				stmts := $1.(*ast.StmtsStmt)
				stmts.Stmts = append(stmts.Stmts, $3)
			}
			if l, ok := yylex.(*Lexer); ok {
				l.stmt = $$
			}
		}
	}

modstmts:
	opt_term modstmt
	{
		if $2 != nil {
			$$ = &ast.StmtsStmt{Stmts: []ast.Stmt{$2}}
		}
		if l, ok := yylex.(*Lexer); ok {
			l.stmt = $$
		}
	}
	| modstmts term modstmt
	{
		if $3 != nil {
			if $1 == nil {
				$$ = &ast.StmtsStmt{Stmts: []ast.Stmt{$3}}
			} else {
				stmts := $1.(*ast.StmtsStmt)
				stmts.Stmts = append(stmts.Stmts, $3)
			}
			if l, ok := yylex.(*Lexer); ok {
				l.stmt = $$
			}
		}
	}

modstmt :
	/* nothing */
	{
		$$ = nil
	}
	| stmt_module
	{
		$$ = $1
	}
	| expr
	{
		$$ = &ast.ExprStmt{Expr: $1}
		$$.SetPosition($1.Position())
	}
	| stmt_var_or_lets
	{
		$$ = $1
	}
	| stmt_struct
	{
		$$ = $1
	}
	| stmt_import
	{
		$$ = $1
	}
  

stmt :
	/* nothing */
	{
		$$ = nil
	}
	| stmt_var_or_lets
	{
		$$ = $1
	}
	| BREAK
	{
		$$ = &ast.BreakStmt{}
		$$.SetPosition($1.Position())
	}
	| CONTINUE
	{
		$$ = &ast.ContinueStmt{}
		$$.SetPosition($1.Position())
	}
	| RETURN exprs
	{
		$$ = &ast.ReturnStmt{Exprs: $2}
		$$.SetPosition($1.Position())
	}
	| THROW expr
	{
		$$ = &ast.ThrowStmt{Expr: $2}
		$$.SetPosition($1.Position())
	}
	| stmt_module
	{
		$$ = $1
	}
	| TRY '{' compstmt '}' CATCH IDENT '{' compstmt '}' FINALLY '{' compstmt '}'
	{
		$$ = &ast.TryStmt{Try: $3, Var: $6.Lit, Catch: $8, Finally: $12}
		$$.SetPosition($1.Position())
	}
	| TRY '{' compstmt '}' CATCH '{' compstmt '}' FINALLY '{' compstmt '}'
	{
		$$ = &ast.TryStmt{Try: $3, Catch: $7, Finally: $11}
		$$.SetPosition($1.Position())
	}
	| TRY '{' compstmt '}' CATCH IDENT '{' compstmt '}'
	{
		$$ = &ast.TryStmt{Try: $3, Var: $6.Lit, Catch: $8}
		$$.SetPosition($1.Position())
	}
	| TRY '{' compstmt '}' CATCH '{' compstmt '}'
	{
		$$ = &ast.TryStmt{Try: $3, Catch: $7}
		$$.SetPosition($1.Position())
	}
	| GO IDENT '(' exprs VARARG ')'
	{
		$$ = &ast.GoroutineStmt{Expr: &ast.CallExpr{Name: $2.Lit, SubExprs: $4, VarArg: true, Go: true}}
		$$.SetPosition($2.Position())
	}
	| GO IDENT '(' exprs ')'
	{
		$$ = &ast.GoroutineStmt{Expr: &ast.CallExpr{Name: $2.Lit, SubExprs: $4, Go: true}}
		$$.SetPosition($2.Position())
	}
	| GO expr '(' exprs VARARG ')'
	{
		$$ = &ast.GoroutineStmt{Expr: &ast.AnonCallExpr{Expr: $2, SubExprs: $4, VarArg: true, Go: true}}
		$$.SetPosition($2.Position())
	}
	| GO expr '(' exprs ')'
	{
		$$ = &ast.GoroutineStmt{Expr: &ast.AnonCallExpr{Expr: $2, SubExprs: $4, Go: true}}
		$$.SetPosition($1.Position())
	}
	| DELETE '(' expr ')'
	{
		$$ = &ast.DeleteStmt{Item: $3}
		$$.SetPosition($1.Position())
	}
	| DELETE '(' expr ',' expr ')'
	{
		$$ = &ast.DeleteStmt{Item: $3, Key: $5}
		$$.SetPosition($1.Position())
	}
	| CLOSE '(' expr ')'
	{
		$$ = &ast.CloseStmt{Expr: $3}
		$$.SetPosition($1.Position())
	}
	| stmt_if
	{
		$$ = $1
	}
	| stmt_for
	{
		$$ = $1
	}
	| stmt_switch
	{
		$$ = $1
	}
	| stmt_import
	{
		$$ = $1
	}
	| stmt_struct
	{
		$$ = $1
	}
	| expr
	{
		$$ = &ast.ExprStmt{Expr: $1}
		$$.SetPosition($1.Position())
	}

stmt_module :
	MODULE '{'
	{
		yylex.Error("can't create anonymous module")
		return 1
	}
	| MODULE IDENT '{' modstmts '}'
	{
		$$ = &ast.ModuleStmt{Name: $2.Lit, Stmt: $4}
		$$.SetPosition($1.Position())
	}

stmt_var_or_lets :
	stmt_var
	{
		$$ = $1
	}
	| stmt_lets
	{
		$$ = $1
	}

stmt_import :
	IMPORT expr
	{
		$$ = &ast.ImportStmt{Name: $2}
		$$.SetPosition($1.Position())
	}
	|
	IMPORT '.' expr
	{
		$$ = &ast.ImportStmt{Name: $3, Local: true}
		$$.SetPosition($1.Position())
	}
	|
	IMPORT expr AS IDENT
	{
		$$ = &ast.ImportStmt{Name: $2, As: $4.Lit}
		$$.SetPosition($1.Position())
	}
	|
	IMPORT '.' expr AS IDENT
	{
		$$ = &ast.ImportStmt{Name: $3, As: $5.Lit, Local: true}
		$$.SetPosition($1.Position())
	}

stmt_var :
	VAR expr_idents '=' exprs
	{
		$$ = &ast.VarStmt{Names: $2, Exprs: $4}
    		$$.SetPosition($1.Position())
	}

stmt_lets :
	expr '=' expr
	{
		$$ = &ast.LetsStmt{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{$3}}
		$$.SetPosition($1.Position())
	}
	| exprs '=' exprs
	{
		if len($1) == 2 && len($3) == 1 {
			if _, ok := $3[0].(*ast.ItemExpr); ok {
				$$ = &ast.LetMapItemStmt{LHSS: $1, RHS: $3[0]}
			} else {
				$$ = &ast.LetsStmt{LHSS: $1, RHSS: $3}
			}
		} else {
			$$ = &ast.LetsStmt{LHSS: $1, RHSS: $3}
		}
	}
	| '(' expr_idents ')' '=' exprs
	{
		yyS := make([]ast.Expr, len($2))
		for i, yyv := range $2 {
			yyS[i] = &ast.IdentExpr{Lit: yyv}
		}
		$$ = &ast.LetsStmt{LHSS: yyS, RHSS: $5, Unpack: true}
	}
	|
	exprs AS '(' expr_idents ')'
	{
		yyS := make([]ast.Expr, len($4))
		for i, yyv := range $4 {
		yyS[i] = &ast.IdentExpr{Lit: yyv}
		}
		$$ = &ast.LetsStmt{LHSS: yyS, RHSS: $1, Unpack: true}
		$$.SetPosition($2.Position())
	}
	|
	exprs AS exprs
	{
		// for maps
		if len($3) == 2 && len($1) == 1 {
			if _, ok := $1[0].(*ast.ItemExpr); ok {
				$$ = &ast.LetMapItemStmt{LHSS: $3, RHS: $1[0]}
			} else {
				$$ = &ast.LetsStmt{LHSS: $3, RHSS: $1}
			}
		} else {
			$$ = &ast.LetsStmt{LHSS: $3, RHSS: $1}
		}
		$$.SetPosition($2.Position())
	}
	| expr EQOPCHAN expr
	{
		$$ = &ast.ChanStmt{LHS: $1, RHS: $3}
		$$.SetPosition($1.Position())
	}
	| exprs EQOPCHAN expr
	{
		if len($1) == 2 {
			chanStmt := &ast.ChanStmt{LHS: $1[0].(ast.Expr), OkExpr: $1[1].(ast.Expr), RHS: $3}
			$$ = chanStmt
			$$.SetPosition(chanStmt.LHS.Position())
		} else if len($1) < 2 {
			yylex.Error("missing expressions on left side of channel operator")
			// TODO: return 1
			$$ = &ast.ChanStmt{RHS: $3}
			$$.SetPosition($2.Position())
		}
	}
stmt_if :
	IF expr '{' compstmt '}'
	{
		$$ = &ast.IfStmt{If: $2, Then: $4, Else: nil}
		$$.SetPosition($1.Position())
	}
	| stmt_if ELSE IF expr '{' compstmt '}'
	{
		ifStmt := $1.(*ast.IfStmt)
		ifStmt.ElseIf = append(ifStmt.ElseIf, &ast.IfStmt{If: $4, Then: $6})
	}
	| stmt_if ELSE '{' compstmt '}'
	{
		ifStmt := $1.(*ast.IfStmt)
		if ifStmt.Else != nil {
			yylex.Error("multiple else statement")
			return 1
		}
		ifStmt.Else = $4
	}

stmt_for :
	FOR '{' compstmt '}'
	{
		$$ = &ast.LoopStmt{Stmt: $3}
		$$.SetPosition($1.Position())
	}
	| FOR expr_idents IN expr '{' compstmt '}'
	{
		if len($2) < 1 {
			yylex.Error("missing identifier")
			return 1
		}
		if len($2) > 2 {
			yylex.Error("too many identifiers")
			return 1
		}
		$$ = &ast.ForStmt{Vars: $2, Value: $4, Stmt: $6}
		$$.SetPosition($1.Position())
	}
	| FOR expr '{' compstmt '}'
	{
		$$ = &ast.LoopStmt{Expr: $2, Stmt: $4}
		$$.SetPosition($1.Position())
	}
	| FOR ';' ';' '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Stmt: $5}
		$$.SetPosition($1.Position())
	}
	| FOR ';' ';' expr '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Expr3: $4, Stmt: $6}
		$$.SetPosition($1.Position())
	}
	| FOR ';' expr ';' '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Expr2: $3, Stmt: $6}
		$$.SetPosition($1.Position())
	}
	| FOR ';' expr ';' expr '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Expr2: $3, Expr3: $5, Stmt: $7}
		$$.SetPosition($1.Position())
	}
	| FOR stmt_var_or_lets ';' ';' '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Stmt1: $2, Stmt: $6}
		$$.SetPosition($1.Position())
	}
	| FOR stmt_var_or_lets ';' ';' expr '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Stmt1: $2, Expr3: $5, Stmt: $7}
		$$.SetPosition($1.Position())
	}
	| FOR stmt_var_or_lets ';' expr ';' '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Stmt1: $2, Expr2: $4, Stmt: $7}
		$$.SetPosition($1.Position())
	}
	| FOR stmt_var_or_lets ';' expr ';' expr '{' compstmt '}'
	{
		$$ = &ast.CForStmt{Stmt1: $2, Expr2: $4, Expr3: $6, Stmt: $8}
		$$.SetPosition($1.Position())
	}

stmt_struct :
	STRUCT IDENT '{' newlines type_data_struct newlines '}'
	{
		$$ = &ast.StructStmt{
			Name: $2.Lit,
			Body: $5,
		}
	}

stmt_switch :
	SWITCH expr '{' opt_newlines stmt_switch_cases opt_newlines '}'
	{
		switchStmt := $5.(*ast.SwitchStmt)
		switchStmt.Expr = $2
		$$ = switchStmt
		$$.SetPosition($1.Position())
	}

stmt_switch_cases :
	/* nothing */
	{
		$$ = &ast.SwitchStmt{}
	}
	| stmt_switch_default
	{
		$$ = &ast.SwitchStmt{Default: $1}
	}
	| stmt_switch_case
	{
		$$ = &ast.SwitchStmt{Cases: []ast.Stmt{$1}}
	}
	| stmt_switch_cases stmt_switch_case
	{
		switchStmt := $1.(*ast.SwitchStmt)
		switchStmt.Cases = append(switchStmt.Cases, $2)
		$$ = switchStmt
	}
	| stmt_switch_cases stmt_switch_default
	{
		switchStmt := $1.(*ast.SwitchStmt)
		if switchStmt.Default != nil {
			yylex.Error("multiple default statement")
			return 1
		}
		switchStmt.Default = $2
	}

stmt_switch_case :
	CASE expr ':' compstmt
	{
		$$ = &ast.SwitchCaseStmt{Exprs: []ast.Expr{$2}, Stmt: $4}
		$$.SetPosition($1.Position())
	}
	| CASE exprs ':' compstmt
	{
		$$ = &ast.SwitchCaseStmt{Exprs: $2, Stmt: $4}
		$$.SetPosition($1.Position())
	}

stmt_switch_default :
	DEFAULT ':' compstmt
	{
		$$ = $3
	}


exprs :
	/* nothing */
	{
		$$ = nil
	}
	| expr 
	{
		$$ = []ast.Expr{$1}
	}
	| exprs ',' opt_newlines expr
	{
		if len($1) == 0 {
			yylex.Error("syntax error: unexpected ','")
			return 1
		}
		$$ = append($1, $4)
	}
	| exprs ',' opt_newlines expr_ident
	{
		if len($1) == 0 {
			yylex.Error("syntax error: unexpected ','")
			return 1
		}
		$$ = append($1, $4)
	}

expr :
	expr_member_or_ident
	{
		$$ = $1
	}
	| expr_literals
	{
		$$ = $1
	}
	| expr '?' expr ':' expr
	{
		$$ = &ast.TernaryOpExpr{Expr: $1, LHS: $3, RHS: $5}
		$$.SetPosition($1.Position())
	}
	| expr NILCOALESCE expr
	{
		$$ = &ast.NilCoalescingOpExpr{LHS: $1, RHS: $3}
		$$.SetPosition($1.Position())
	}
	| FUNC '(' expr_idents ')' '{' compstmt '}'
	{
		$$ = &ast.FuncExpr{Params: $3, Stmt: $6}
		$$.SetPosition($1.Position())
	}
	| FUNC '(' expr_idents VARARG ')' '{' compstmt '}'
	{
		$$ = &ast.FuncExpr{Params: $3, Stmt: $7, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| FUNC IDENT '(' expr_idents ')' '{' compstmt '}'
	{
		$$ = &ast.FuncExpr{Name: $2.Lit, Params: $4, Stmt: $7}
		$$.SetPosition($1.Position())
	}
	| FUNC IDENT '(' expr_idents VARARG ')' '{' compstmt '}'
	{
		$$ = &ast.FuncExpr{Name: $2.Lit, Params: $4, Stmt: $8, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| FUNC '|' IDENT '|' IDENT '(' expr_idents VARARG ')' '{' compstmt '}'
	{
		$$ = &ast.FuncExpr{Recv: $3.Lit, Name: $5.Lit, Params: $7, Stmt: $11, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| FUNC '|' IDENT '|' IDENT '(' expr_idents ')' '{' compstmt '}'
	{
		$$ = &ast.FuncExpr{Recv: $3.Lit, Name: $5.Lit, Params: $7, Stmt: $10}
		$$.SetPosition($1.Position())
	}
	| '[' ']'
	{
		$$ = &ast.ArrayExpr{}
		if l, ok := yylex.(*Lexer); ok { $$.SetPosition(l.pos) }
	}
	| '[' opt_newlines exprs opt_comma_newlines ']'
	{
		$$ = &ast.ArrayExpr{Exprs: $3}
		if l, ok := yylex.(*Lexer); ok { $$.SetPosition(l.pos) }
	}
	| slice_count type_data '{' opt_newlines exprs opt_comma_newlines '}'
	{
		$$ = &ast.ArrayExpr{Exprs: $5, TypeData: &ast.TypeStruct{Kind: ast.TypeSlice, SubType: $2, Dimensions: $1}}
		if l, ok := yylex.(*Lexer); ok { $$.SetPosition(l.pos) }
	}
	| '(' expr ')'
	{
		$$ = &ast.ParenExpr{SubExpr: $2}
		if l, ok := yylex.(*Lexer); ok { $$.SetPosition(l.pos) }
	}
	| IDENT '(' exprs VARARG ')'
	{
		$$ = &ast.CallExpr{Name: $1.Lit, SubExprs: $3, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| IDENT '(' exprs VARARG ')' '?'
	{
		$$ = &ast.CallErrExpr{Name: $1.Lit, SubExprs: $3, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| IDENT '(' exprs ')'
	{
		$$ = &ast.CallExpr{Name: $1.Lit, SubExprs: $3}
		$$.SetPosition($1.Position())
	}
	| IDENT '(' exprs ')' '?'
	{
		$$ = &ast.CallErrExpr{Name: $1.Lit, SubExprs: $3}
		$$.SetPosition($1.Position())
	}
	| expr '(' exprs VARARG ')'
	{
		$$ = &ast.AnonCallExpr{Expr: $1, SubExprs: $3, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| expr '(' exprs VARARG ')' '?'
	{
		$$ = &ast.AnonCallErrExpr{Expr: $1, SubExprs: $3, VarArg: true}
		$$.SetPosition($1.Position())
	}
	| expr '(' exprs ')'
	{
		$$ = &ast.AnonCallExpr{Expr: $1, SubExprs: $3}
		$$.SetPosition($1.Position())
	}
	| expr '(' exprs ')' '?'
	{
		$$ = &ast.AnonCallErrExpr{Expr: $1, SubExprs: $3}
		$$.SetPosition($1.Position())
	}
	| expr_ident '[' expr ']'
	{
		$$ = &ast.ItemExpr{Item: $1, Index: $3}
		$$.SetPosition($1.Position())
	}
	| expr '[' expr ']'
	{
		$$ = &ast.ItemExpr{Item: $1, Index: $3}
		$$.SetPosition($1.Position())
	}
	| LEN '(' expr ')'
	{
		$$ = &ast.LenExpr{Expr: $3}
		$$.SetPosition($1.Position())
	}
	| NEW '(' type_data ')'
	{
		if $3.Kind == ast.TypeDefault {
			$3.Kind = ast.TypePtr
			$$ = &ast.MakeExpr{TypeData: $3}
		} else {
			$$ = &ast.MakeExpr{TypeData: &ast.TypeStruct{Kind: ast.TypePtr, SubType: $3}}
		}
		$$.SetPosition($1.Position())
	}
	| MAKE '(' type_data ')'
	{
		$$ = &ast.MakeExpr{TypeData: $3}
		$$.SetPosition($1.Position())
	}
	| MAKE '(' type_data ',' expr ')'
	{
		$$ = &ast.MakeExpr{TypeData: $3, LenExpr: $5}
		$$.SetPosition($1.Position())
	}
	| MAKE '(' type_data ',' expr ',' expr ')'
	{
		$$ = &ast.MakeExpr{TypeData: $3, LenExpr: $5, CapExpr: $7}
		$$.SetPosition($1.Position())
	}
	| MAKE '(' TYPE IDENT ',' expr ')'
	{
		$$ = &ast.MakeTypeExpr{Name: $4.Lit, Type: $6}
		$$.SetPosition($1.Position())
	}
	| expr IN expr
	{
		$$ = &ast.IncludeExpr{ItemExpr: $1, ListExpr: $3}
		$$.SetPosition($1.Position())
	}
	| MAP '{' opt_newlines expr_map opt_comma_newlines '}'
	{
		$4.TypeData = &ast.TypeStruct{Kind: ast.TypeMap, Key: &ast.TypeStruct{Name: "interface"}, SubType: &ast.TypeStruct{Name: "interface"}}
		$$ = $4
		$$.SetPosition($1.Position())
	}
	| MAP '[' type_data ']' type_data '{' opt_newlines expr_map opt_comma_newlines '}'
	{
		$8.TypeData = &ast.TypeStruct{Kind: ast.TypeMap, Key: $3, SubType: $5}
		$$ = $8
		$$.SetPosition($1.Position())
	}
	| '{' opt_newlines expr_map opt_comma_newlines '}'
	{
		$$ = $3
		$$.SetPosition($3.Position())
	}
	| expr_slice
	{
		$$ = $1
		$$.SetPosition($1.Position())
	}
	| expr_chan
	{
		$$ = $1
		$$.SetPosition($1.Position())
	}
	| expr_unary
	| expr_binary
	| expr_lets

expr_idents :
	{
		$$ = []string{}
	}
	| IDENT
	{
		$$ = []string{$1.Lit}
	}
	| expr_idents ',' opt_newlines IDENT
	{
		if len($1) == 0 {
			yylex.Error("syntax error: unexpected ','")
			return 1
		}
		$$ = append($1, $4.Lit)
	}

type_data :
	IDENT
	{
		$$ = &ast.TypeStruct{Name: $1.Lit}
	}
	| type_data '.' IDENT
	{
		if $1.Kind != ast.TypeDefault {
			yylex.Error("not type default")
			return 1
		}
		$1.Env = append($1.Env, $1.Name)
		$1.Name = $3.Lit
	}
	| '*' type_data
	{
		if $2.Kind == ast.TypeDefault {
			$2.Kind = ast.TypePtr
			$$ = $2
		} else {
			$$ = &ast.TypeStruct{Kind: ast.TypePtr, SubType: $2}
		}
	}
	| slice_count type_data
	{
		if $2.Kind == ast.TypeDefault {
			$2.Kind = ast.TypeSlice
			$2.Dimensions = $1
			$$ = $2
		} else {
			$$ = &ast.TypeStruct{Kind: ast.TypeSlice, SubType: $2, Dimensions: $1}
		}
	}
	| MAP '[' type_data ']' type_data
	{
		$$ = &ast.TypeStruct{Kind: ast.TypeMap, Key: $3, SubType: $5}
	}
	| CHAN type_data
	{
		if $2.Kind == ast.TypeDefault {
			$2.Kind = ast.TypeChan
			$$ = $2
		} else {
			$$ = &ast.TypeStruct{Kind: ast.TypeChan, SubType: $2}
		}
	}
	| STRUCT '{' opt_newlines type_data_struct opt_newlines '}'
	{
		$$ = $4
	}

type_data_struct :
	IDENT type_data
	{
		$$ = &ast.TypeStruct{
			Kind: ast.TypeStructType,
			StructNames: []string{$1.Lit},
			StructTypes: []*ast.TypeStruct{$2},
			Name: $2.Name,
		}
	}
	| type_data_struct comma_newlines IDENT type_data
	{
		if $$ == nil || len($1.StructNames) == 0 {
			yylex.Error("syntax error: expected type declaration")
			return 1
		}
		if $3.Lit[0] >= 97 {
			yylex.Error("struct declarations cannot start with a lowercase letter")
			return 1
		}

		$$.StructNames = append($$.StructNames, $3.Lit)
		$$.StructTypes = append($$.StructTypes, $4)
	}

slice_count :
	'[' ']'
	{
		$$ = 1
	}
	| '[' ']' slice_count
	{
		$$ = $3 + 1
	}

expr_member_or_ident :
	expr_member
	{
		$$ = $1
	}
	| expr_ident
	{
		$$ = $1
	}

expr_member :
	expr '.' IDENT
	{
		$$ = &ast.MemberExpr{Expr: $1, Name: $3.Lit}
		$$.SetPosition($1.Position())
	}

expr_ident :
	IDENT
	{
		$$ = &ast.IdentExpr{Lit: $1.Lit}
		$$.SetPosition($1.Position())
	}

expr_literals :
	'-' NUMBER
	{
		num, err := toNumber("-" + $2.Lit)
		if err != nil {
			yylex.Error("invalid number: -" + $2.Lit)
      return 1
		}
		$$ = &ast.LiteralExpr{Literal: num}
		$$.SetPosition($2.Position())
	}
	| NUMBER
	{
		yyN := $1.Lit
		num, err := toNumber(yyN)
		if err != nil {
			yylex.Error("invalid number: " + yyN)
			return 1
		}
		$$ = &ast.LiteralExpr{Literal: num}
		$$.SetPosition($1.Position())
	}
	| STRING
	{
		$$ = &ast.LiteralExpr{Literal: stringToValue($1.Lit)}
		$$.SetPosition($1.Position())
	}
	| TRUE
	{
		$$ = &ast.LiteralExpr{Literal: trueValue}
		$$.SetPosition($1.Position())
	}
	| FALSE
	{
		$$ = &ast.LiteralExpr{Literal: falseValue}
		$$.SetPosition($1.Position())
	}
	| NIL
	{
		$$ = &ast.LiteralExpr{Literal: nilValue}
		$$.SetPosition($1.Position())
	}

expr_map :
	/* nothing */
	{
		$$ = &ast.MapExpr{}
	}
	| expr ':' expr
	{
		$$ = &ast.MapExpr{Keys: []ast.Expr{$1}, Values: []ast.Expr{$3}}
	}
	| expr_map ',' opt_newlines expr ':' expr
	{
		if $1.Keys == nil {
			yylex.Error("syntax error: unexpected ','")
			return 1
		}
		$$.Keys = append($$.Keys, $4)
		$$.Values = append($$.Values, $6)
	}

expr_slice :
	expr_ident '[' expr ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: $3, End: $5}
	}
	| expr_ident '[' expr ':' ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: $3, End: nil}
	}
	| expr_ident '[' ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: nil, End: $4}
	}
	| expr_ident '[' ':' expr ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, End: $4, Cap: $6}
	}
	| expr_ident '[' expr ':' expr ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: $3, End: $5, Cap: $7}
	}
	| expr '[' expr ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: $3, End: $5}
	}
	| expr '[' expr ':' ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: $3, End: nil}
	}
	| expr '[' ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: nil, End: $4}
	}
	| expr '[' ':' expr ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, End: $4, Cap: $6}
	}
	| expr '[' expr ':' expr ':' expr ']'
	{
		$$ = &ast.SliceExpr{Item: $1, Begin: $3, End: $5, Cap: $7}
	}

expr_chan :
	expr OPCHAN expr
	{
		$$ = &ast.ChanExpr{LHS: $1, RHS: $3}
	}
	| OPCHAN expr
	{
		$$ = &ast.ChanExpr{RHS: $2}
	}

expr_unary :
	'-' expr %prec UNARY
	{
		$$ = &ast.UnaryExpr{Operator: "-", Expr: $2}
		$$.SetPosition($2.Position())
	}
	| '!' expr %prec UNARY
	{
		$$ = &ast.UnaryExpr{Operator: "!", Expr: $2}
		$$.SetPosition($2.Position())
	}
	| '^' expr %prec UNARY
	{
		$$ = &ast.UnaryExpr{Operator: "^", Expr: $2}
		$$.SetPosition($2.Position())
	}
	| '&' expr %prec UNARY
	{
		$$ = &ast.AddrExpr{Expr: $2}
		$$.SetPosition($2.Position())
	}
	| '*' expr %prec UNARY
	{
		$$ = &ast.DerefExpr{Expr: $2}
		$$.SetPosition($2.Position())
	}

expr_binary :
	op_multiply
	{
		$$ = &ast.OpExpr{Op: $1}
		$$.SetPosition($1.Position())
	}
	| op_add
	{
		$$ = &ast.OpExpr{Op: $1}
		$$.SetPosition($1.Position())
	}
	| op_comparison
	{
		$$ = &ast.OpExpr{Op: $1}
		$$.SetPosition($1.Position())
	}
	| op_binary
	{
		$$ = &ast.OpExpr{Op: $1}
		$$.SetPosition($1.Position())
	}

expr_lets:
	expr PLUSPLUS
	{
		rhs := &ast.OpExpr{Op: &ast.AddOperator{LHS: $1, Operator: "+", RHS: oneLiteral}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr MINUSMINUS
	{
		rhs := &ast.OpExpr{Op: &ast.AddOperator{LHS: $1, Operator: "-", RHS: oneLiteral}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr PLUSEQ expr
	{
		rhs := &ast.OpExpr{Op: &ast.AddOperator{LHS: $1, Operator: "+", RHS: $3}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr MINUSEQ expr
	{
		rhs := &ast.OpExpr{Op: &ast.AddOperator{LHS: $1, Operator: "-", RHS: $3}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr OREQ expr
	{
		rhs := &ast.OpExpr{Op: &ast.AddOperator{LHS: $1, Operator: "|", RHS: $3}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr MULEQ expr
	{
		rhs := &ast.OpExpr{Op: &ast.MultiplyOperator{LHS: $1, Operator: "*", RHS: $3}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr DIVEQ expr
	{
		rhs := &ast.OpExpr{Op: &ast.MultiplyOperator{LHS: $1, Operator: "/", RHS: $3}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}
	| expr ANDEQ expr
	{
		rhs := &ast.OpExpr{Op: &ast.MultiplyOperator{LHS: $1, Operator: "&", RHS: $3}}
		rhs.Op.SetPosition($1.Position())
		rhs.SetPosition($1.Position())
		$$ = &ast.LetsExpr{LHSS: []ast.Expr{$1}, RHSS: []ast.Expr{rhs}}
		$$.SetPosition($1.Position())
	}


op_multiply :
	expr '*' expr
	{
		$$ = &ast.MultiplyOperator{LHS: $1, Operator: "*", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '/' expr
	{
		$$ = &ast.MultiplyOperator{LHS: $1, Operator: "/", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '%' expr
	{
		$$ = &ast.MultiplyOperator{LHS: $1, Operator: "%", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr SHIFTLEFT expr
	{
		$$ = &ast.MultiplyOperator{LHS: $1, Operator: "<<", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr SHIFTRIGHT expr
	{
		$$ = &ast.MultiplyOperator{LHS: $1, Operator: ">>", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '&' expr
	{
		$$ = &ast.MultiplyOperator{LHS: $1, Operator: "&", RHS: $3}
		$$.SetPosition($1.Position())
	}

op_add :
	expr '+' expr
	{
		$$ = &ast.AddOperator{LHS: $1, Operator: "+", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '-' expr
	{
		$$ = &ast.AddOperator{LHS: $1, Operator: "-", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '|' expr
	{
		$$ = &ast.AddOperator{LHS: $1, Operator: "|", RHS: $3}
		$$.SetPosition($1.Position())
	}

op_comparison :
	expr EQEQ expr
	{
		$$ = &ast.ComparisonOperator{LHS: $1, Operator: "==", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr NEQ expr
	{
		$$ = &ast.ComparisonOperator{LHS: $1, Operator: "!=", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '<' expr
	{
		$$ = &ast.ComparisonOperator{LHS: $1, Operator: "<", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr LE expr
	{
		$$ = &ast.ComparisonOperator{LHS: $1, Operator: "<=", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr '>' expr
	{
		$$ = &ast.ComparisonOperator{LHS: $1, Operator: ">", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr GE expr
	{
		$$ = &ast.ComparisonOperator{LHS: $1, Operator: ">=", RHS: $3}
		$$.SetPosition($1.Position())
	}

op_binary :
	expr ANDAND expr
	{
		$$ = &ast.BinaryOperator{LHS: $1, Operator: "&&", RHS: $3}
		$$.SetPosition($1.Position())
	}
	| expr OROR expr
	{
		$$ = &ast.BinaryOperator{LHS: $1, Operator: "||", RHS: $3}
		$$.SetPosition($1.Position())
	}


opt_term :
	/* nothing */
	| term
	
term :
	';' newlines
	| newlines
	| ';'

opt_newlines : 
	/* nothing */
	| newlines

newlines : 
	newline
	| newlines newline

newline : '\n'

comma_newlines:
	',' newlines
	| newlines
	| ','

opt_comma_newlines : 
	/* nothing */
	| ',' newlines
	| newlines
	| ','

%%