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exp/template: allow range actions to declare a key and element variable.
{{range $key, $element := pipeline}}
This CL is smaller than it looks due to some rearrangement and renaming.
R=rsc, r
CC=golang-dev
https://golang.org/cl/4709047
This commit is contained in:
Rob Pike
parent
aec89c4c40
commit
fc1f0bd5e9
@ -155,9 +155,18 @@ initialization has syntax
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$variable := pipeline
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where $variable is the name of the variable. The one exception is a pipeline in
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a range action; in ranges, the variable is set to the successive elements of the
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iteration.
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where $variable is the name of the variable.
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The one exception is a pipeline in a range action; in ranges, the variable is
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set to the successive elements of the iteration. Also, a range may declare two
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variables, separated by a comma:
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$index, $element := pipeline
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In this case $index and $element are set to the successive values of the
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array/slice index or map key and element, respectively. Note that if there is
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only one variable, it is assigned the element; this is opposite to the
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convention in Go range clauses.
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When execution begins, $ is set to the data argument passed to Execute, that is,
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to the starting value of dot.
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@ -46,9 +46,9 @@ func (s *state) pop(mark int) {
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s.vars = s.vars[0:mark]
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}
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// setTop overwrites the top variable on the stack. Used by range iterations.
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func (s *state) setTop(value reflect.Value) {
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s.vars[len(s.vars)-1].value = value
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// setVar overwrites the top-nth variable on the stack. Used by range iterations.
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func (s *state) setVar(n int, value reflect.Value) {
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s.vars[len(s.vars)-n].value = value
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}
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// varValue returns the value of the named variable.
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@ -191,9 +191,13 @@ func (s *state) walkRange(dot reflect.Value, r *rangeNode) {
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}
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for i := 0; i < val.Len(); i++ {
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elem := val.Index(i)
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// Set $x to the element rather than the slice.
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if r.pipe.decl != nil {
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s.setTop(elem)
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// Set top var (lexically the second if there are two) to the element.
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if len(r.pipe.decl) > 0 {
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s.setVar(1, elem)
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}
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// Set next var (lexically the first if there are two) to the index.
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if len(r.pipe.decl) > 1 {
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s.setVar(2, reflect.ValueOf(i))
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}
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s.walk(elem, r.list)
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}
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@ -204,9 +208,13 @@ func (s *state) walkRange(dot reflect.Value, r *rangeNode) {
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}
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for _, key := range val.MapKeys() {
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elem := val.MapIndex(key)
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// Set $x to the key rather than the map.
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if r.pipe.decl != nil {
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s.setTop(elem)
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// Set top var (lexically the second if there are two) to the element.
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if len(r.pipe.decl) > 0 {
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s.setVar(1, elem)
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}
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// Set next var (lexically the first if there are two) to the key.
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if len(r.pipe.decl) > 1 {
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s.setVar(2, key)
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}
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s.walk(elem, r.list)
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}
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@ -255,8 +263,8 @@ func (s *state) evalPipeline(dot reflect.Value, pipe *pipeNode) (value reflect.V
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value = reflect.ValueOf(value.Interface()) // lovely!
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}
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}
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if pipe.decl != nil {
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s.push(pipe.decl.ident[0], value)
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for _, variable := range pipe.decl {
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s.push(variable.ident[0], value)
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}
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return value
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}
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@ -195,14 +195,8 @@ var execTests = []execTest{
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// Variables.
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{"$ int", "{{$}}", "123", 123, true},
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{"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true},
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{"range $x SI", "{{range $x := .SI}}<{{$x}}>{{end}}", "<3><4><5>", tVal, true},
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{"range $x PSI", "{{range $x := .PSI}}<{{$x}}>{{end}}", "<21><22><23>", tVal, true},
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{"if $x with $y int", "{{if $x := true}}{{with $y := .I}}{{$x}},{{$y}}{{end}}{{end}}", "true,17", tVal, true},
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{"if $x with $x int", "{{if $x := true}}{{with $x := .I}}{{$x}},{{end}}{{$x}}{{end}}", "17,true", tVal, true},
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{"$.I", "{{$.I}}", "17", tVal, true},
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{"$.U.V", "{{$.U.V}}", "v", tVal, true},
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{"with $x struct.U.V", "{{with $x := $}}{{$.U.V}}{{end}}", "v", tVal, true},
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// Pointers.
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{"*int", "{{.PI}}", "23", tVal, true},
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@ -253,6 +247,8 @@ var execTests = []execTest{
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{"if slice", "{{if .SI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
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{"if emptymap", "{{if .MSIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
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{"if map", "{{if .MSI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
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{"if $x with $y int", "{{if $x := true}}{{with $y := .I}}{{$x}},{{$y}}{{end}}{{end}}", "true,17", tVal, true},
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{"if $x with $x int", "{{if $x := true}}{{with $x := .I}}{{$x}},{{end}}{{$x}}{{end}}", "17,true", tVal, true},
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// Print etc.
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{"print", `{{print "hello, print"}}`, "hello, print", tVal, true},
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@ -312,6 +308,8 @@ var execTests = []execTest{
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{"with emptymap", "{{with .MSIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
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{"with map", "{{with .MSIone}}{{.}}{{else}}EMPTY{{end}}", "map[one:1]", tVal, true},
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{"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "v", tVal, true},
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{"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true},
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{"with $x struct.U.V", "{{with $x := $}}{{$.U.V}}{{end}}", "v", tVal, true},
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// Range.
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{"range []int", "{{range .SI}}-{{.}}-{{end}}", "-3--4--5-", tVal, true},
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@ -325,6 +323,11 @@ var execTests = []execTest{
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{"range map else", "{{range .MSI | .MSort}}-{{.}}-{{else}}EMPTY{{end}}", "-one--three--two-", tVal, true},
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{"range empty map else", "{{range .MSIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
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{"range empty interface", "{{range .Empty3}}-{{.}}-{{else}}EMPTY{{end}}", "-7--8-", tVal, true},
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{"range $x SI", "{{range $x := .SI}}<{{$x}}>{{end}}", "<3><4><5>", tVal, true},
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{"range $x $y SI", "{{range $x, $y := .SI}}<{{$x}}={{$y}}>{{end}}", "<0=3><1=4><2=5>", tVal, true},
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{"range $x MSIone", "{{range $x := .MSIone}}<{{$x}}>{{end}}", "<1>", tVal, true},
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{"range $x $y MSIone", "{{range $x, $y := .MSIone}}<{{$x}}={{$y}}>{{end}}", "<one=1>", tVal, true},
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{"range $x PSI", "{{range $x := .PSI}}<{{$x}}>{{end}}", "<21><22><23>", tVal, true},
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// Cute examples.
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{"or as if true", `{{or .SI "slice is empty"}}`, "[3 4 5]", tVal, true},
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@ -35,11 +35,12 @@ func (i item) String() string {
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type itemType int
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const (
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itemError itemType = iota // error occurred; value is text of error
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itemBool // boolean constant
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itemChar // character constant
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itemComplex // complex constant (1+2i); imaginary is just a number
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itemColonEquals // colon-equals (':=') introducing a declaration
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itemError itemType = iota // error occurred; value is text of error
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itemBool // boolean constant
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itemChar // printable ASCII character; grab bag for comma etc.
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itemCharConstant // character constant
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itemComplex // complex constant (1+2i); imaginary is just a number
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itemColonEquals // colon-equals (':=') introducing a declaration
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itemEOF
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itemField // alphanumeric identifier, starting with '.', possibly chained ('.x.y')
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itemIdentifier // alphanumeric identifier
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@ -65,21 +66,22 @@ const (
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// Make the types prettyprint.
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var itemName = map[itemType]string{
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itemError: "error",
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itemBool: "bool",
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itemChar: "char",
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itemComplex: "complex",
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itemColonEquals: ":=",
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itemEOF: "EOF",
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itemField: "field",
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itemIdentifier: "identifier",
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itemLeftDelim: "left delim",
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itemNumber: "number",
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itemPipe: "pipe",
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itemRawString: "raw string",
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itemRightDelim: "right delim",
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itemString: "string",
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itemVariable: "variable",
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itemError: "error",
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itemBool: "bool",
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itemChar: "char",
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itemCharConstant: "charconst",
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itemComplex: "complex",
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itemColonEquals: ":=",
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itemEOF: "EOF",
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itemField: "field",
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itemIdentifier: "identifier",
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itemLeftDelim: "left delim",
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itemNumber: "number",
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itemPipe: "pipe",
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itemRawString: "raw string",
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itemRightDelim: "right delim",
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itemString: "string",
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itemVariable: "variable",
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// keywords
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itemDot: ".",
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itemDefine: "define",
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@ -315,6 +317,9 @@ func lexInsideAction(l *lexer) stateFn {
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case isAlphaNumeric(r):
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l.backup()
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return lexIdentifier
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case r <= unicode.MaxASCII && unicode.IsPrint(r):
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l.emit(itemChar)
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return lexInsideAction
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default:
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return l.errorf("unrecognized character in action: %#U", r)
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}
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@ -369,7 +374,7 @@ Loop:
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break Loop
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}
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}
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l.emit(itemChar)
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l.emit(itemCharConstant)
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return lexInsideAction
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}
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@ -36,6 +36,14 @@ var lexTests = []lexTest{
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{itemText, "-world"},
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tEOF,
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}},
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{"punctuation", "{{,@%}}", []item{
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tLeft,
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{itemChar, ","},
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{itemChar, "@"},
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{itemChar, "%"},
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tRight,
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tEOF,
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}},
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{"empty action", `{{}}`, []item{tLeft, tRight, tEOF}},
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{"for", `{{for }}`, []item{tLeft, tFor, tRight, tEOF}},
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{"quote", `{{"abc \n\t\" "}}`, []item{tLeft, tQuote, tRight, tEOF}},
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@ -55,13 +63,13 @@ var lexTests = []lexTest{
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}},
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{"characters", `{{'a' '\n' '\'' '\\' '\u00FF' '\xFF' '本'}}`, []item{
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tLeft,
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{itemChar, `'a'`},
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{itemChar, `'\n'`},
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{itemChar, `'\''`},
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{itemChar, `'\\'`},
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{itemChar, `'\u00FF'`},
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{itemChar, `'\xFF'`},
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{itemChar, `'本'`},
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{itemCharConstant, `'a'`},
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{itemCharConstant, `'\n'`},
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{itemCharConstant, `'\''`},
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{itemCharConstant, `'\\'`},
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{itemCharConstant, `'\u00FF'`},
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{itemCharConstant, `'\xFF'`},
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{itemCharConstant, `'本'`},
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tRight,
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tEOF,
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}},
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@ -127,11 +135,29 @@ var lexTests = []lexTest{
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{itemText, " outro"},
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tEOF,
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}},
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{"declaration", "{{$v := 3}}", []item{
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tLeft,
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{itemVariable, "$v"},
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{itemColonEquals, ":="},
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{itemNumber, "3"},
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tRight,
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tEOF,
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}},
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{"2 declarations", "{{$v , $w := 3}}", []item{
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tLeft,
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{itemVariable, "$v"},
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{itemChar, ","},
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{itemVariable, "$w"},
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{itemColonEquals, ":="},
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{itemNumber, "3"},
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tRight,
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tEOF,
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}},
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// errors
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{"badchar", "#{{#}}", []item{
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{"badchar", "#{{\x01}}", []item{
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{itemText, "#"},
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tLeft,
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{itemError, "unrecognized character in action: U+0023 '#'"},
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{itemError, "unrecognized character in action: U+0001"},
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}},
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{"unclosed action", "{{\n}}", []item{
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tLeft,
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@ -140,11 +140,11 @@ func (t *textNode) String() string {
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type pipeNode struct {
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nodeType
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line int
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decl *variableNode
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decl []*variableNode
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cmds []*commandNode
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}
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func newPipeline(line int, decl *variableNode) *pipeNode {
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func newPipeline(line int, decl []*variableNode) *pipeNode {
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return &pipeNode{nodeType: nodePipe, line: line, decl: decl}
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}
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@ -154,7 +154,7 @@ func (p *pipeNode) append(command *commandNode) {
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func (p *pipeNode) String() string {
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if p.decl != nil {
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return fmt.Sprintf("%s := %v", p.decl.ident, p.cmds)
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return fmt.Sprintf("%v := %v", p.decl, p.cmds)
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}
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return fmt.Sprintf("%v", p.cmds)
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}
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@ -287,7 +287,7 @@ type numberNode struct {
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func newNumber(text string, typ itemType) (*numberNode, os.Error) {
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n := &numberNode{nodeType: nodeNumber, text: text}
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switch typ {
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case itemChar:
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case itemCharConstant:
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rune, _, tail, err := strconv.UnquoteChar(text[1:], text[0])
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if err != nil {
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return nil, err
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@ -704,20 +704,30 @@ func (t *Template) action() (n node) {
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// field or command
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// pipeline "|" pipeline
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func (t *Template) pipeline(context string) (pipe *pipeNode) {
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var decl *variableNode
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// Is there a declaration?
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if v := t.peek(); v.typ == itemVariable {
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t.next()
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if ce := t.peek(); ce.typ == itemColonEquals {
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var decl []*variableNode
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// Are there declarations?
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for {
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if v := t.peek(); v.typ == itemVariable {
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t.next()
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decl = newVariable(v.val)
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if len(decl.ident) != 1 {
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t.errorf("illegal variable in declaration: %s", v.val)
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if next := t.peek(); next.typ == itemColonEquals || next.typ == itemChar {
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t.next()
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variable := newVariable(v.val)
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if len(variable.ident) != 1 {
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t.errorf("illegal variable in declaration: %s", v.val)
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}
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decl = append(decl, variable)
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t.vars = append(t.vars, v.val)
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if next.typ == itemChar && next.val == "," {
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if context == "range" && len(decl) < 2 {
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continue
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}
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t.errorf("too many declarations in %s", context)
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}
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} else {
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t.backup2(v)
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}
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t.vars = append(t.vars, v.val)
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} else {
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t.backup2(v)
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}
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break
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}
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pipe = newPipeline(t.lex.lineNumber(), decl)
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for {
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@ -727,7 +737,8 @@ func (t *Template) pipeline(context string) (pipe *pipeNode) {
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t.errorf("missing value for %s", context)
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}
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return
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case itemBool, itemChar, itemComplex, itemDot, itemField, itemIdentifier, itemVariable, itemNumber, itemRawString, itemString:
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case itemBool, itemCharConstant, itemComplex, itemDot, itemField, itemIdentifier,
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itemVariable, itemNumber, itemRawString, itemString:
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t.backup()
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pipe.append(t.command())
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default:
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@ -848,7 +859,7 @@ Loop:
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cmd.append(newField(token.val))
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case itemBool:
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cmd.append(newBool(token.val == "true"))
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case itemChar, itemComplex, itemNumber:
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case itemCharConstant, itemComplex, itemNumber:
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number, err := newNumber(token.val, token.typ)
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if err != nil {
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t.error(err)
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@ -77,7 +77,7 @@ func TestNumberParse(t *testing.T) {
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var c complex128
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typ := itemNumber
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if test.text[0] == '\'' {
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typ = itemChar
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typ = itemCharConstant
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} else {
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_, err := fmt.Sscan(test.text, &c)
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if err == nil {
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@ -174,7 +174,7 @@ var parseTests = []parseTest{
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{"$ invocation", "{{$}}", noError,
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"[(action: [(command: [V=[$]])])]"},
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{"variable invocation", "{{with $x := 3}}{{$x 23}}{{end}}", noError,
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"[({{with [$x] := [(command: [N=3])]}} [(action: [(command: [V=[$x] N=23])])])]"},
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"[({{with [V=[$x]] := [(command: [N=3])]}} [(action: [(command: [V=[$x] N=23])])])]"},
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{"variable with fields", "{{$.I}}", noError,
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"[(action: [(command: [V=[$ I]])])]"},
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{"multi-word command", "{{printf `%d` 23}}", noError,
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@ -182,7 +182,7 @@ var parseTests = []parseTest{
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{"pipeline", "{{.X|.Y}}", noError,
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`[(action: [(command: [F=[X]]) (command: [F=[Y]])])]`},
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{"pipeline with decl", "{{$x := .X|.Y}}", noError,
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`[(action: [$x] := [(command: [F=[X]]) (command: [F=[Y]])])]`},
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`[(action: [V=[$x]] := [(command: [F=[X]]) (command: [F=[Y]])])]`},
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{"declaration", "{{.X|.Y}}", noError,
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`[(action: [(command: [F=[X]]) (command: [F=[Y]])])]`},
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{"simple if", "{{if .X}}hello{{end}}", noError,
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@ -223,6 +223,9 @@ var parseTests = []parseTest{
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{"declare with field", "{{with $x.Y := 4}}{{end}}", hasError, ""},
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{"template with field ref", "{{template .X}}", hasError, ""},
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{"template with var", "{{template $v}}", hasError, ""},
|
||||
{"invalid punctuation", "{{printf 3, 4}}", hasError, ""},
|
||||
{"multidecl outside range", "{{with $v, $u := 3}}{{end}}", hasError, ""},
|
||||
{"too many decls in range", "{{range $u, $v, $w := 3}}{{end}}", hasError, ""},
|
||||
}
|
||||
|
||||
func TestParse(t *testing.T) {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user