863 lines
18 KiB
Plaintext
863 lines
18 KiB
Plaintext
// BUILD file parser.
|
|
|
|
// This is a yacc grammar. Its lexer is in lex.go.
|
|
//
|
|
// For a good introduction to writing yacc grammars, see
|
|
// Kernighan and Pike's book The Unix Programming Environment.
|
|
//
|
|
// The definitive yacc manual is
|
|
// Stephen C. Johnson and Ravi Sethi, "Yacc: A Parser Generator",
|
|
// online at http://plan9.bell-labs.com/sys/doc/yacc.pdf.
|
|
|
|
%{
|
|
package build
|
|
%}
|
|
|
|
// The generated parser puts these fields in a struct named yySymType.
|
|
// (The name %union is historical, but it is inaccurate for Go.)
|
|
%union {
|
|
// input tokens
|
|
tok string // raw input syntax
|
|
str string // decoding of quoted string
|
|
pos Position // position of token
|
|
triple bool // was string triple quoted?
|
|
|
|
// partial syntax trees
|
|
expr Expr
|
|
exprs []Expr
|
|
forc *ForClause
|
|
ifs []*IfClause
|
|
forifs *ForClauseWithIfClausesOpt
|
|
forsifs []*ForClauseWithIfClausesOpt
|
|
string *StringExpr
|
|
strings []*StringExpr
|
|
block CodeBlock
|
|
|
|
// supporting information
|
|
comma Position // position of trailing comma in list, if present
|
|
lastRule Expr // most recent rule, to attach line comments to
|
|
}
|
|
|
|
// These declarations set the type for a $ reference ($$, $1, $2, ...)
|
|
// based on the kind of symbol it refers to. Other fields can be referred
|
|
// to explicitly, as in $<tok>1.
|
|
//
|
|
// %token is for input tokens generated by the lexer.
|
|
// %type is for higher-level grammar rules defined here.
|
|
//
|
|
// It is possible to put multiple tokens per line, but it is easier to
|
|
// keep ordered using a sparser one-per-line list.
|
|
|
|
%token <pos> '%'
|
|
%token <pos> '('
|
|
%token <pos> ')'
|
|
%token <pos> '*'
|
|
%token <pos> '+'
|
|
%token <pos> ','
|
|
%token <pos> '-'
|
|
%token <pos> '.'
|
|
%token <pos> '/'
|
|
%token <pos> ':'
|
|
%token <pos> '<'
|
|
%token <pos> '='
|
|
%token <pos> '>'
|
|
%token <pos> '['
|
|
%token <pos> ']'
|
|
%token <pos> '{'
|
|
%token <pos> '}'
|
|
|
|
// By convention, yacc token names are all caps.
|
|
// However, we do not want to export them from the Go package
|
|
// we are creating, so prefix them all with underscores.
|
|
|
|
%token <pos> _AUGM // augmented assignment
|
|
%token <pos> _AND // keyword and
|
|
%token <pos> _COMMENT // top-level # comment
|
|
%token <pos> _EOF // end of file
|
|
%token <pos> _EQ // operator ==
|
|
%token <pos> _FOR // keyword for
|
|
%token <pos> _GE // operator >=
|
|
%token <pos> _IDENT // non-keyword identifier or number
|
|
%token <pos> _IF // keyword if
|
|
%token <pos> _ELSE // keyword else
|
|
%token <pos> _ELIF // keyword elif
|
|
%token <pos> _IN // keyword in
|
|
%token <pos> _IS // keyword is
|
|
%token <pos> _LAMBDA // keyword lambda
|
|
%token <pos> _LOAD // keyword load
|
|
%token <pos> _LE // operator <=
|
|
%token <pos> _NE // operator !=
|
|
%token <pos> _NOT // keyword not
|
|
%token <pos> _OR // keyword or
|
|
%token <pos> _PYTHON // uninterpreted Python block
|
|
%token <pos> _STRING // quoted string
|
|
%token <pos> _DEF // keyword def
|
|
%token <pos> _RETURN // keyword return
|
|
%token <pos> _INDENT // indentation
|
|
%token <pos> _UNINDENT // unindentation
|
|
|
|
%type <pos> comma_opt
|
|
%type <expr> expr
|
|
%type <expr> expr_opt
|
|
%type <expr> primary_expr
|
|
%type <exprs> exprs
|
|
%type <exprs> exprs_opt
|
|
%type <exprs> primary_exprs
|
|
%type <forc> for_clause
|
|
%type <forifs> for_clause_with_if_clauses_opt
|
|
%type <forsifs> for_clauses_with_if_clauses_opt
|
|
%type <expr> ident
|
|
%type <ifs> if_clauses_opt
|
|
%type <exprs> stmts
|
|
%type <exprs> stmt // a simple_stmt or a for/if/def block
|
|
%type <expr> block_stmt // a single for/if/def statement
|
|
%type <expr> if_else_block // a single if-else statement
|
|
%type <exprs> simple_stmt // One or many small_stmts on one line, e.g. 'a = f(x); return str(a)'
|
|
%type <expr> small_stmt // A single statement, e.g. 'a = f(x)'
|
|
%type <exprs> small_stmts_continuation // A sequence of `';' small_stmt`
|
|
%type <expr> keyvalue
|
|
%type <exprs> keyvalues
|
|
%type <exprs> keyvalues_no_comma
|
|
%type <string> string
|
|
%type <strings> strings
|
|
%type <block> suite
|
|
|
|
// Operator precedence.
|
|
// Operators listed lower in the table bind tighter.
|
|
|
|
// We tag rules with this fake, low precedence to indicate
|
|
// that when the rule is involved in a shift/reduce
|
|
// conflict, we prefer that the parser shift (try for a longer parse).
|
|
// Shifting is the default resolution anyway, but stating it explicitly
|
|
// silences yacc's warning for that specific case.
|
|
%left ShiftInstead
|
|
|
|
%left '\n'
|
|
%left _ASSERT
|
|
// '=' and augmented assignments have the lowest precedence
|
|
// e.g. "x = a if c > 0 else 'bar'"
|
|
// followed by
|
|
// 'if' and 'else' which have lower precedence than all other operators.
|
|
// e.g. "a, b if c > 0 else 'foo'" is either a tuple of (a,b) or 'foo'
|
|
// and not a tuple of "(a, (b if ... ))"
|
|
%left '=' _AUGM
|
|
%left _IF _ELSE _ELIF
|
|
%left ','
|
|
%left ':'
|
|
%left _IN _NOT _IS
|
|
%left _OR
|
|
%left _AND
|
|
%left '<' '>' _EQ _NE _LE _GE
|
|
%left '+' '-'
|
|
%left '*' '/' '%'
|
|
%left '.' '[' '('
|
|
%right _UNARY
|
|
%left _STRING
|
|
|
|
%%
|
|
|
|
// Grammar rules.
|
|
//
|
|
// A note on names: if foo is a rule, then foos is a sequence of foos
|
|
// (with interleaved commas or other syntax as appropriate)
|
|
// and foo_opt is an optional foo.
|
|
|
|
file:
|
|
stmts _EOF
|
|
{
|
|
yylex.(*input).file = &File{Stmt: $1}
|
|
return 0
|
|
}
|
|
|
|
suite:
|
|
'\n' _INDENT stmts _UNINDENT
|
|
{
|
|
$$ = CodeBlock{
|
|
Start: $2,
|
|
Statements: $3,
|
|
End: End{Pos: $4},
|
|
}
|
|
}
|
|
| simple_stmt
|
|
{
|
|
// simple_stmt is never empty
|
|
start, _ := $1[0].Span()
|
|
_, end := $1[len($1)-1].Span()
|
|
$$ = CodeBlock{
|
|
Start: start,
|
|
Statements: $1,
|
|
End: End{Pos: end},
|
|
}
|
|
}
|
|
|
|
stmts:
|
|
{
|
|
$$ = nil
|
|
$<lastRule>$ = nil
|
|
}
|
|
| stmts stmt
|
|
{
|
|
// If this statement follows a comment block,
|
|
// attach the comments to the statement.
|
|
if cb, ok := $<lastRule>1.(*CommentBlock); ok {
|
|
$$ = append($1[:len($1)-1], $2...)
|
|
$2[0].Comment().Before = cb.After
|
|
$<lastRule>$ = $2[len($2)-1]
|
|
break
|
|
}
|
|
|
|
// Otherwise add to list.
|
|
$$ = append($1, $2...)
|
|
$<lastRule>$ = $2[len($2)-1]
|
|
|
|
// Consider this input:
|
|
//
|
|
// foo()
|
|
// # bar
|
|
// baz()
|
|
//
|
|
// If we've just parsed baz(), the # bar is attached to
|
|
// foo() as an After comment. Make it a Before comment
|
|
// for baz() instead.
|
|
if x := $<lastRule>1; x != nil {
|
|
com := x.Comment()
|
|
// stmt is never empty
|
|
$2[0].Comment().Before = com.After
|
|
com.After = nil
|
|
}
|
|
}
|
|
| stmts '\n'
|
|
{
|
|
// Blank line; sever last rule from future comments.
|
|
$$ = $1
|
|
$<lastRule>$ = nil
|
|
}
|
|
| stmts _COMMENT '\n'
|
|
{
|
|
$$ = $1
|
|
$<lastRule>$ = $<lastRule>1
|
|
if $<lastRule>$ == nil {
|
|
cb := &CommentBlock{Start: $2}
|
|
$$ = append($$, cb)
|
|
$<lastRule>$ = cb
|
|
}
|
|
com := $<lastRule>$.Comment()
|
|
com.After = append(com.After, Comment{Start: $2, Token: $<tok>2})
|
|
}
|
|
|
|
stmt:
|
|
simple_stmt
|
|
{
|
|
$$ = $1
|
|
}
|
|
| block_stmt
|
|
{
|
|
$$ = []Expr{$1}
|
|
}
|
|
|
|
block_stmt:
|
|
_DEF _IDENT '(' exprs_opt ')' ':' suite
|
|
{
|
|
$$ = &FuncDef{
|
|
Start: $1,
|
|
Name: $<tok>2,
|
|
ListStart: $3,
|
|
Args: $4,
|
|
Body: $7,
|
|
End: $7.End,
|
|
ForceCompact: forceCompact($3, $4, $5),
|
|
ForceMultiLine: forceMultiLine($3, $4, $5),
|
|
}
|
|
}
|
|
| _FOR primary_exprs _IN expr ':' suite
|
|
{
|
|
$$ = &ForLoop{
|
|
Start: $1,
|
|
LoopVars: $2,
|
|
Iterable: $4,
|
|
Body: $6,
|
|
End: $6.End,
|
|
}
|
|
}
|
|
| if_else_block
|
|
{
|
|
$$ = $1
|
|
}
|
|
|
|
if_else_block:
|
|
_IF expr ':' suite
|
|
{
|
|
$$ = &IfElse{
|
|
Start: $1,
|
|
Conditions: []Condition{
|
|
Condition{
|
|
If: $2,
|
|
Then: $4,
|
|
},
|
|
},
|
|
End: $4.End,
|
|
}
|
|
}
|
|
| if_else_block elif expr ':' suite
|
|
{
|
|
block := $1.(*IfElse)
|
|
block.Conditions = append(block.Conditions, Condition{
|
|
If: $3,
|
|
Then: $5,
|
|
})
|
|
block.End = $5.End
|
|
$$ = block
|
|
}
|
|
| if_else_block _ELSE ':' suite
|
|
{
|
|
block := $1.(*IfElse)
|
|
block.Conditions = append(block.Conditions, Condition{
|
|
Then: $4,
|
|
})
|
|
block.End = $4.End
|
|
$$ = block
|
|
}
|
|
|
|
elif:
|
|
_ELSE _IF
|
|
| _ELIF
|
|
|
|
simple_stmt:
|
|
small_stmt small_stmts_continuation semi_opt '\n'
|
|
{
|
|
$$ = append([]Expr{$1}, $2...)
|
|
$<lastRule>$ = $$[len($$)-1]
|
|
}
|
|
|
|
small_stmts_continuation:
|
|
{
|
|
$$ = []Expr{}
|
|
}
|
|
| small_stmts_continuation ';' small_stmt
|
|
{
|
|
$$ = append($1, $3)
|
|
}
|
|
|
|
small_stmt:
|
|
expr %prec ShiftInstead
|
|
| _RETURN expr
|
|
{
|
|
_, end := $2.Span()
|
|
$$ = &ReturnExpr{
|
|
X: $2,
|
|
End: end,
|
|
}
|
|
}
|
|
| _RETURN
|
|
{
|
|
$$ = &ReturnExpr{End: $1}
|
|
}
|
|
| _PYTHON
|
|
{
|
|
$$ = &PythonBlock{Start: $1, Token: $<tok>1}
|
|
}
|
|
|
|
semi_opt:
|
|
| ';'
|
|
|
|
primary_expr:
|
|
ident
|
|
| primary_expr '.' _IDENT
|
|
{
|
|
$$ = &DotExpr{
|
|
X: $1,
|
|
Dot: $2,
|
|
NamePos: $3,
|
|
Name: $<tok>3,
|
|
}
|
|
}
|
|
| _LOAD '(' exprs_opt ')'
|
|
{
|
|
$$ = &CallExpr{
|
|
X: &LiteralExpr{Start: $1, Token: "load"},
|
|
ListStart: $2,
|
|
List: $3,
|
|
End: End{Pos: $4},
|
|
ForceCompact: forceCompact($2, $3, $4),
|
|
ForceMultiLine: forceMultiLine($2, $3, $4),
|
|
}
|
|
}
|
|
| primary_expr '(' exprs_opt ')'
|
|
{
|
|
$$ = &CallExpr{
|
|
X: $1,
|
|
ListStart: $2,
|
|
List: $3,
|
|
End: End{Pos: $4},
|
|
ForceCompact: forceCompact($2, $3, $4),
|
|
ForceMultiLine: forceMultiLine($2, $3, $4),
|
|
}
|
|
}
|
|
| primary_expr '[' expr ']'
|
|
{
|
|
$$ = &IndexExpr{
|
|
X: $1,
|
|
IndexStart: $2,
|
|
Y: $3,
|
|
End: $4,
|
|
}
|
|
}
|
|
| primary_expr '[' expr_opt ':' expr_opt ']'
|
|
{
|
|
$$ = &SliceExpr{
|
|
X: $1,
|
|
SliceStart: $2,
|
|
From: $3,
|
|
FirstColon: $4,
|
|
To: $5,
|
|
End: $6,
|
|
}
|
|
}
|
|
| primary_expr '[' expr_opt ':' expr_opt ':' expr_opt ']'
|
|
{
|
|
$$ = &SliceExpr{
|
|
X: $1,
|
|
SliceStart: $2,
|
|
From: $3,
|
|
FirstColon: $4,
|
|
To: $5,
|
|
SecondColon: $6,
|
|
Step: $7,
|
|
End: $8,
|
|
}
|
|
}
|
|
| primary_expr '(' expr for_clauses_with_if_clauses_opt ')'
|
|
{
|
|
$$ = &CallExpr{
|
|
X: $1,
|
|
ListStart: $2,
|
|
List: []Expr{
|
|
&ListForExpr{
|
|
Brack: "",
|
|
Start: $2,
|
|
X: $3,
|
|
For: $4,
|
|
End: End{Pos: $5},
|
|
},
|
|
},
|
|
End: End{Pos: $5},
|
|
}
|
|
}
|
|
| strings %prec ShiftInstead
|
|
{
|
|
if len($1) == 1 {
|
|
$$ = $1[0]
|
|
break
|
|
}
|
|
$$ = $1[0]
|
|
for _, x := range $1[1:] {
|
|
_, end := $$.Span()
|
|
$$ = binary($$, end, "+", x)
|
|
}
|
|
}
|
|
| '[' exprs_opt ']'
|
|
{
|
|
$$ = &ListExpr{
|
|
Start: $1,
|
|
List: $2,
|
|
Comma: $<comma>2,
|
|
End: End{Pos: $3},
|
|
ForceMultiLine: forceMultiLine($1, $2, $3),
|
|
}
|
|
}
|
|
| '[' expr for_clauses_with_if_clauses_opt ']'
|
|
{
|
|
exprStart, _ := $2.Span()
|
|
$$ = &ListForExpr{
|
|
Brack: "[]",
|
|
Start: $1,
|
|
X: $2,
|
|
For: $3,
|
|
End: End{Pos: $4},
|
|
ForceMultiLine: $1.Line != exprStart.Line,
|
|
}
|
|
}
|
|
| '(' expr for_clauses_with_if_clauses_opt ')'
|
|
{
|
|
exprStart, _ := $2.Span()
|
|
$$ = &ListForExpr{
|
|
Brack: "()",
|
|
Start: $1,
|
|
X: $2,
|
|
For: $3,
|
|
End: End{Pos: $4},
|
|
ForceMultiLine: $1.Line != exprStart.Line,
|
|
}
|
|
}
|
|
| '{' keyvalue for_clauses_with_if_clauses_opt '}'
|
|
{
|
|
exprStart, _ := $2.Span()
|
|
$$ = &ListForExpr{
|
|
Brack: "{}",
|
|
Start: $1,
|
|
X: $2,
|
|
For: $3,
|
|
End: End{Pos: $4},
|
|
ForceMultiLine: $1.Line != exprStart.Line,
|
|
}
|
|
}
|
|
| '{' keyvalues '}'
|
|
{
|
|
$$ = &DictExpr{
|
|
Start: $1,
|
|
List: $2,
|
|
Comma: $<comma>2,
|
|
End: End{Pos: $3},
|
|
ForceMultiLine: forceMultiLine($1, $2, $3),
|
|
}
|
|
}
|
|
| '{' exprs_opt '}'
|
|
{
|
|
$$ = &SetExpr{
|
|
Start: $1,
|
|
List: $2,
|
|
Comma: $<comma>2,
|
|
End: End{Pos: $3},
|
|
ForceMultiLine: forceMultiLine($1, $2, $3),
|
|
}
|
|
}
|
|
| '(' exprs_opt ')'
|
|
{
|
|
if len($2) == 1 && $<comma>2.Line == 0 {
|
|
// Just a parenthesized expression, not a tuple.
|
|
$$ = &ParenExpr{
|
|
Start: $1,
|
|
X: $2[0],
|
|
End: End{Pos: $3},
|
|
ForceMultiLine: forceMultiLine($1, $2, $3),
|
|
}
|
|
} else {
|
|
$$ = &TupleExpr{
|
|
Start: $1,
|
|
List: $2,
|
|
Comma: $<comma>2,
|
|
End: End{Pos: $3},
|
|
ForceCompact: forceCompact($1, $2, $3),
|
|
ForceMultiLine: forceMultiLine($1, $2, $3),
|
|
}
|
|
}
|
|
}
|
|
| '-' primary_expr %prec _UNARY { $$ = unary($1, $<tok>1, $2) }
|
|
|
|
expr:
|
|
primary_expr
|
|
| _LAMBDA exprs ':' expr
|
|
{
|
|
$$ = &LambdaExpr{
|
|
Lambda: $1,
|
|
Var: $2,
|
|
Colon: $3,
|
|
Expr: $4,
|
|
}
|
|
}
|
|
| _NOT expr %prec _UNARY { $$ = unary($1, $<tok>1, $2) }
|
|
| '*' expr %prec _UNARY { $$ = unary($1, $<tok>1, $2) }
|
|
| expr '*' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '%' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '/' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '+' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '-' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '<' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '>' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _EQ expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _LE expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _NE expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _GE expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr '=' expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _AUGM expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _IN expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _NOT _IN expr { $$ = binary($1, $2, "not in", $4) }
|
|
| expr _OR expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _AND expr { $$ = binary($1, $2, $<tok>2, $3) }
|
|
| expr _IS expr
|
|
{
|
|
if b, ok := $3.(*UnaryExpr); ok && b.Op == "not" {
|
|
$$ = binary($1, $2, "is not", b.X)
|
|
} else {
|
|
$$ = binary($1, $2, $<tok>2, $3)
|
|
}
|
|
}
|
|
| expr _IF expr _ELSE expr
|
|
{
|
|
$$ = &ConditionalExpr{
|
|
Then: $1,
|
|
IfStart: $2,
|
|
Test: $3,
|
|
ElseStart: $4,
|
|
Else: $5,
|
|
}
|
|
}
|
|
|
|
expr_opt:
|
|
{
|
|
$$ = nil
|
|
}
|
|
| expr
|
|
|
|
// comma_opt is an optional comma. If the comma is present,
|
|
// the rule's value is the position of the comma. Otherwise
|
|
// the rule's value is the zero position. Tracking this
|
|
// lets us distinguish (x) and (x,).
|
|
comma_opt:
|
|
{
|
|
$$ = Position{}
|
|
}
|
|
| ','
|
|
|
|
keyvalue:
|
|
expr ':' expr {
|
|
$$ = &KeyValueExpr{
|
|
Key: $1,
|
|
Colon: $2,
|
|
Value: $3,
|
|
}
|
|
}
|
|
|
|
keyvalues_no_comma:
|
|
keyvalue
|
|
{
|
|
$$ = []Expr{$1}
|
|
}
|
|
| keyvalues_no_comma ',' keyvalue
|
|
{
|
|
$$ = append($1, $3)
|
|
}
|
|
|
|
keyvalues:
|
|
keyvalues_no_comma
|
|
{
|
|
$$ = $1
|
|
}
|
|
| keyvalues_no_comma ','
|
|
{
|
|
$$ = $1
|
|
}
|
|
|
|
exprs:
|
|
expr
|
|
{
|
|
$$ = []Expr{$1}
|
|
}
|
|
| exprs ',' expr
|
|
{
|
|
$$ = append($1, $3)
|
|
}
|
|
|
|
exprs_opt:
|
|
{
|
|
$$, $<comma>$ = nil, Position{}
|
|
}
|
|
| exprs comma_opt
|
|
{
|
|
$$, $<comma>$ = $1, $2
|
|
}
|
|
|
|
primary_exprs:
|
|
primary_expr
|
|
{
|
|
$$ = []Expr{$1}
|
|
}
|
|
| primary_exprs ',' primary_expr
|
|
{
|
|
$$ = append($1, $3)
|
|
}
|
|
|
|
string:
|
|
_STRING
|
|
{
|
|
$$ = &StringExpr{
|
|
Start: $1,
|
|
Value: $<str>1,
|
|
TripleQuote: $<triple>1,
|
|
End: $1.add($<tok>1),
|
|
Token: $<tok>1,
|
|
}
|
|
}
|
|
|
|
strings:
|
|
string
|
|
{
|
|
$$ = []*StringExpr{$1}
|
|
}
|
|
| strings string
|
|
{
|
|
$$ = append($1, $2)
|
|
}
|
|
|
|
ident:
|
|
_IDENT
|
|
{
|
|
$$ = &LiteralExpr{Start: $1, Token: $<tok>1}
|
|
}
|
|
|
|
for_clause:
|
|
_FOR primary_exprs _IN expr
|
|
{
|
|
$$ = &ForClause{
|
|
For: $1,
|
|
Var: $2,
|
|
In: $3,
|
|
Expr: $4,
|
|
}
|
|
}
|
|
|
|
for_clause_with_if_clauses_opt:
|
|
for_clause if_clauses_opt {
|
|
$$ = &ForClauseWithIfClausesOpt{
|
|
For: $1,
|
|
Ifs: $2,
|
|
}
|
|
}
|
|
|
|
for_clauses_with_if_clauses_opt:
|
|
for_clause_with_if_clauses_opt
|
|
{
|
|
$$ = []*ForClauseWithIfClausesOpt{$1}
|
|
}
|
|
| for_clauses_with_if_clauses_opt for_clause_with_if_clauses_opt {
|
|
$$ = append($1, $2)
|
|
}
|
|
|
|
if_clauses_opt:
|
|
{
|
|
$$ = nil
|
|
}
|
|
| if_clauses_opt _IF expr
|
|
{
|
|
$$ = append($1, &IfClause{
|
|
If: $2,
|
|
Cond: $3,
|
|
})
|
|
}
|
|
|
|
%%
|
|
|
|
// Go helper code.
|
|
|
|
// unary returns a unary expression with the given
|
|
// position, operator, and subexpression.
|
|
func unary(pos Position, op string, x Expr) Expr {
|
|
return &UnaryExpr{
|
|
OpStart: pos,
|
|
Op: op,
|
|
X: x,
|
|
}
|
|
}
|
|
|
|
// binary returns a binary expression with the given
|
|
// operands, position, and operator.
|
|
func binary(x Expr, pos Position, op string, y Expr) Expr {
|
|
_, xend := x.Span()
|
|
ystart, _ := y.Span()
|
|
return &BinaryExpr{
|
|
X: x,
|
|
OpStart: pos,
|
|
Op: op,
|
|
LineBreak: xend.Line < ystart.Line,
|
|
Y: y,
|
|
}
|
|
}
|
|
|
|
// isSimpleExpression returns whether an expression is simple and allowed to exist in
|
|
// compact forms of sequences.
|
|
// The formal criteria are the following: an expression is considered simple if it's
|
|
// a literal (variable, string or a number), a literal with a unary operator or an empty sequence.
|
|
func isSimpleExpression(expr *Expr) bool {
|
|
switch x := (*expr).(type) {
|
|
case *LiteralExpr, *StringExpr:
|
|
return true
|
|
case *UnaryExpr:
|
|
_, ok := x.X.(*LiteralExpr)
|
|
return ok
|
|
case *ListExpr:
|
|
return len(x.List) == 0
|
|
case *TupleExpr:
|
|
return len(x.List) == 0
|
|
case *DictExpr:
|
|
return len(x.List) == 0
|
|
case *SetExpr:
|
|
return len(x.List) == 0
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// forceCompact returns the setting for the ForceCompact field for a call or tuple.
|
|
//
|
|
// NOTE 1: The field is called ForceCompact, not ForceSingleLine,
|
|
// because it only affects the formatting associated with the call or tuple syntax,
|
|
// not the formatting of the arguments. For example:
|
|
//
|
|
// call([
|
|
// 1,
|
|
// 2,
|
|
// 3,
|
|
// ])
|
|
//
|
|
// is still a compact call even though it runs on multiple lines.
|
|
//
|
|
// In contrast the multiline form puts a linebreak after the (.
|
|
//
|
|
// call(
|
|
// [
|
|
// 1,
|
|
// 2,
|
|
// 3,
|
|
// ],
|
|
// )
|
|
//
|
|
// NOTE 2: Because of NOTE 1, we cannot use start and end on the
|
|
// same line as a signal for compact mode: the formatting of an
|
|
// embedded list might move the end to a different line, which would
|
|
// then look different on rereading and cause buildifier not to be
|
|
// idempotent. Instead, we have to look at properties guaranteed
|
|
// to be preserved by the reformatting, namely that the opening
|
|
// paren and the first expression are on the same line and that
|
|
// each subsequent expression begins on the same line as the last
|
|
// one ended (no line breaks after comma).
|
|
func forceCompact(start Position, list []Expr, end Position) bool {
|
|
if len(list) <= 1 {
|
|
// The call or tuple will probably be compact anyway; don't force it.
|
|
return false
|
|
}
|
|
|
|
// If there are any named arguments or non-string, non-literal
|
|
// arguments, cannot force compact mode.
|
|
line := start.Line
|
|
for _, x := range list {
|
|
start, end := x.Span()
|
|
if start.Line != line {
|
|
return false
|
|
}
|
|
line = end.Line
|
|
if !isSimpleExpression(&x) {
|
|
return false
|
|
}
|
|
}
|
|
return end.Line == line
|
|
}
|
|
|
|
// forceMultiLine returns the setting for the ForceMultiLine field.
|
|
func forceMultiLine(start Position, list []Expr, end Position) bool {
|
|
if len(list) > 1 {
|
|
// The call will be multiline anyway, because it has multiple elements. Don't force it.
|
|
return false
|
|
}
|
|
|
|
if len(list) == 0 {
|
|
// Empty list: use position of brackets.
|
|
return start.Line != end.Line
|
|
}
|
|
|
|
// Single-element list.
|
|
// Check whether opening bracket is on different line than beginning of
|
|
// element, or closing bracket is on different line than end of element.
|
|
elemStart, elemEnd := list[0].Span()
|
|
return start.Line != elemStart.Line || end.Line != elemEnd.Line
|
|
}
|