github.com/bazelbuild/buildtools v0.0.0-20180226164855-80c7f0d45d7e

Used only by github.com/bazelbuild/bazel-gazelle, expecting 80c7f0d45d7e

vendor/github.com/bazelbuild/buildtools/build/print.go

@@ -23,6 +23,9 @@ import (
 	"strings"
 )
 
+const nestedIndentation = 2 // Indentation of nested blocks
+const listIndentation = 4   // Indentation of multiline expressions
+
 // Format returns the formatted form of the given BUILD file.
 func Format(f *File) []byte {
 	pr := &printer{}
@@ -118,7 +121,19 @@ func (p *printer) file(f *File) {
 		p.newline()
 	}
 
-	for i, stmt := range f.Stmt {
+	p.statements(f.Stmt)
+
+	for _, com := range f.After {
+		p.printf("%s", strings.TrimSpace(com.Token))
+		p.newline()
+	}
+
+	// If the last expression is in an indented code block there can be spaces in the last line.
+	p.trim()
+}
+
+func (p *printer) statements(stmts []Expr) {
+	for i, stmt := range stmts {
 		switch stmt := stmt.(type) {
 		case *CommentBlock:
 			// comments already handled
@@ -128,11 +143,17 @@ func (p *printer) file(f *File) {
 				p.printf("%s", strings.TrimSpace(com.Token))
 				p.newline()
 			}
-			p.printf("%s", stmt.Token) // includes trailing newline
+			p.printf("%s", stmt.Token)
+			p.newline()
 
 		default:
 			p.expr(stmt, precLow)
-			p.newline()
+
+			// Print an empty line break after the expression unless it's a code block.
+			// For a code block, the line break is generated by its last statement.
+			if !isCodeBlock(stmt) {
+				p.newline()
+			}
 		}
 
 		for _, com := range stmt.Comment().After {
@@ -140,28 +161,26 @@ func (p *printer) file(f *File) {
 			p.newline()
 		}
 
-		if i+1 < len(f.Stmt) && !compactStmt(stmt, f.Stmt[i+1]) {
+		if i+1 < len(stmts) && !compactStmt(stmt, stmts[i+1], p.margin == 0) {
 			p.newline()
 		}
 	}
-
-	for _, com := range f.After {
-		p.printf("%s", strings.TrimSpace(com.Token))
-		p.newline()
-	}
 }
 
 // compactStmt reports whether the pair of statements s1, s2
 // should be printed without an intervening blank line.
 // We omit the blank line when both are subinclude statements
 // and the second one has no leading comments.
-func compactStmt(s1, s2 Expr) bool {
+func compactStmt(s1, s2 Expr, isTopLevel bool) bool {
 	if len(s2.Comment().Before) > 0 {
 		return false
 	}
 
-	return (isCall(s1, "subinclude") || isCall(s1, "load")) &&
-		(isCall(s2, "subinclude") || isCall(s2, "load"))
+	if isTopLevel {
+		return isCall(s1, "load") && isCall(s2, "load")
+	} else {
+		return !(isCodeBlock(s1) || isCodeBlock(s2))
+	}
 }
 
 // isCall reports whether x is a call to a function with the given name.
@@ -177,6 +196,20 @@ func isCall(x Expr, name string) bool {
 	return nam.Token == name
 }
 
+// isCodeBlock checks if the statement is a code block (def, if, for, etc.)
+func isCodeBlock(x Expr) bool {
+	switch x.(type) {
+	case *FuncDef:
+		return true
+	case *ForLoop:
+		return true
+	case *IfElse:
+		return true
+	default:
+		return false
+	}
+}
+
 // Expression formatting.
 
 // The expression formatter must introduce parentheses to force the
@@ -220,6 +253,11 @@ const (
 var opPrec = map[string]int{
 	"=":   precAssign,
 	"+=":  precAssign,
+	"-=":  precAssign,
+	"*=":  precAssign,
+	"/=":  precAssign,
+	"//=": precAssign,
+	"%=":  precAssign,
 	"or":  precOr,
 	"and": precAnd,
 	"<":   precCmp,
@@ -232,6 +270,7 @@ var opPrec = map[string]int{
 	"-":   precAdd,
 	"*":   precMultiply,
 	"/":   precMultiply,
+	"//":  precMultiply,
 	"%":   precMultiply,
 }
 
@@ -327,12 +366,18 @@ func (p *printer) expr(v Expr, outerPrec int) {
 		addParen(precSuffix)
 		p.expr(v.X, precSuffix)
 		p.printf("[")
-		if v.Y != nil {
-			p.expr(v.Y, precLow)
+		if v.From != nil {
+			p.expr(v.From, precLow)
 		}
 		p.printf(":")
-		if v.Z != nil {
-			p.expr(v.Z, precLow)
+		if v.To != nil {
+			p.expr(v.To, precLow)
+		}
+		if v.SecondColon.Byte != 0 {
+			p.printf(":")
+			if v.Step != nil {
+				p.expr(v.Step, precLow)
+			}
 		}
 		p.printf("]")
 
@@ -379,7 +424,7 @@ func (p *printer) expr(v Expr, outerPrec int) {
 		if v.LineBreak {
 			p.margin = p.indent()
 			if v.Op == "=" {
-				p.margin += 4
+				p.margin += listIndentation
 			}
 		}
 
@@ -427,6 +472,61 @@ func (p *printer) expr(v Expr, outerPrec int) {
 		p.expr(v.Test, precSuffix)
 		p.printf(" else ")
 		p.expr(v.Else, precSuffix)
+
+	case *ReturnExpr:
+		p.printf("return")
+		if v.X != nil {
+			p.printf(" ")
+			p.expr(v.X, precSuffix)
+		}
+
+	case *FuncDef:
+		p.printf("def ")
+		p.printf(v.Name)
+		p.seq("()", v.Args, &v.End, modeCall, v.ForceCompact, v.ForceMultiLine)
+		p.printf(":")
+		p.margin += nestedIndentation
+		p.newline()
+		p.statements(v.Body.Statements)
+		p.margin -= nestedIndentation
+
+	case *ForLoop:
+		p.printf("for ")
+		for i, loopVar := range v.LoopVars {
+			if i > 0 {
+				p.printf(", ")
+			}
+			p.expr(loopVar, precLow)
+		}
+		p.printf(" in ")
+		p.expr(v.Iterable, precLow)
+		p.printf(":")
+		p.margin += nestedIndentation
+		p.newline()
+		p.statements(v.Body.Statements)
+		p.margin -= nestedIndentation
+
+	case *IfElse:
+		for i, block := range v.Conditions {
+			if i == 0 {
+				p.printf("if ")
+			} else if block.If == nil {
+				p.newline()
+				p.printf("else")
+			} else {
+				p.newline()
+				p.printf("elif ")
+			}
+
+			if block.If != nil {
+				p.expr(block.If, precLow)
+			}
+			p.printf(":")
+			p.margin += nestedIndentation
+			p.newline()
+			p.statements(block.Then.Statements)
+			p.margin -= nestedIndentation
+		}
 	}
 
 	// Add closing parenthesis if needed.
@@ -452,6 +552,7 @@ const (
 	modeTuple // (x,)
 	modeParen // (x)
 	modeDict  // {x:y}
+	modeSeq   // x, y
 )
 
 // seq formats a list of values inside a given bracket pair (brack = "()", "[]", "{}").
@@ -504,7 +605,7 @@ func (p *printer) seq(brack string, list []Expr, end *End, mode seqMode, forceCo
 
 	default:
 		// Multi-line form.
-		p.margin += 4
+		p.margin += listIndentation
 		for i, x := range list {
 			// If we are about to break the line before the first
 			// element and there are trailing end-of-line comments
@@ -528,7 +629,7 @@ func (p *printer) seq(brack string, list []Expr, end *End, mode seqMode, forceCo
 			p.newline()
 			p.printf("%s", strings.TrimSpace(com.Token))
 		}
-		p.margin -= 4
+		p.margin -= listIndentation
 		p.newline()
 	}
 	p.depth--
@@ -566,7 +667,7 @@ func (p *printer) listFor(v *ListForExpr) {
 
 	if multiLine {
 		if v.Brack != "" {
-			p.margin += 4
+			p.margin += listIndentation
 		}
 		p.newline()
 	}
@@ -602,7 +703,7 @@ func (p *printer) listFor(v *ListForExpr) {
 			p.printf("%s", strings.TrimSpace(com.Token))
 		}
 		if v.Brack != "" {
-			p.margin -= 4
+			p.margin -= listIndentation
 		}
 		p.newline()
 	}
@@ -612,3 +713,7 @@ func (p *printer) listFor(v *ListForExpr) {
 		p.depth--
 	}
 }
+
+func (p *printer) isTopLevel() bool {
+	return p.margin == 0
+}