Merge pull request #67 from aisbergg/feat-loop-mod-expr

Allow loop modifiers to be more than just literals
osteele · Aug 23, 2023 · 66a8e52 · 66a8e52
2 parents 9bd9c58 + c50fc96
commit 66a8e52
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Showing 7 changed files with 276 additions and 248 deletions.
diff --git a/expressions/expressions.y b/expressions/expressions.y
@@ -2,7 +2,6 @@
 package expressions
 import (
 	"fmt"
-	"math"
 	"github.com/osteele/liquid/values"
 )
 
@@ -26,7 +25,7 @@ func init() {
    loopmods loopModifiers
    filter_params []valueFn
 }
-%type <f> expr rel filtered cond int_or_var loop_expr
+%type<f> expr rel filtered cond
 %type<filter_params> filter_params
 %type<exprs> exprs expr2
 %type<cycle> cycle
@@ -84,25 +83,13 @@ string: LITERAL {
 	$$ = s
 };
 
-loop: IDENTIFIER IN loop_expr loop_modifiers {
+loop: IDENTIFIER IN filtered loop_modifiers {
 	name, expr, mods := $1, $3, $4
 	$$ = Loop{name, &expression{expr}, mods}
 }
 ;
 
-loop_expr : '(' int_or_var DOTDOT int_or_var ')' {
-  $$ = makeRangeExpr($2, $4)
-}
-| filtered
-;
-
-// TODO DRY w/ expr
-int_or_var:
-  LITERAL { val := $1; $$ = func(Context) values.Value { return values.ValueOf(val) } }
-| IDENTIFIER { name := $1; $$ = func(ctx Context) values.Value { return values.ValueOf(ctx.Get(name)) } }
-;
-
-loop_modifiers: /* empty */ { $$ = loopModifiers{Cols: math.MaxInt32} }
+loop_modifiers: /* empty */ { $$ = loopModifiers{} }
 | loop_modifiers IDENTIFIER {
 	switch $2 {
 	case "reversed":
@@ -112,26 +99,14 @@ loop_modifiers: /* empty */ { $$ = loopModifiers{Cols: math.MaxInt32} }
 	}
 	$$ = $1
 }
-| loop_modifiers KEYWORD LITERAL { // TODO can this be a variable?
-	switch $2 {
+| loop_modifiers KEYWORD expr {
+    switch $2 {
 	case "cols":
-		cols, ok := $3.(int)
-		if !ok {
-			panic(SyntaxError(fmt.Sprintf("loop cols must an integer")))
-		}
-		$1.Cols = cols
+		$1.Cols = &expression{$3}
 	case "limit":
-		limit, ok := $3.(int)
-		if !ok {
-			panic(SyntaxError(fmt.Sprintf("loop limit must an integer")))
-		}
-		$1.Limit = &limit
+		$1.Limit = &expression{$3}
 	case "offset":
-		offset, ok := $3.(int)
-		if !ok {
-			panic(SyntaxError(fmt.Sprintf("loop offset must an integer")))
-		}
-		$1.Offset = offset
+		$1.Offset = &expression{$3}
 	default:
 		panic(SyntaxError(fmt.Sprintf("undefined loop modifier %q", $2)))
 	}
@@ -144,6 +119,7 @@ expr:
 | IDENTIFIER { name := $1; $$ = func(ctx Context) values.Value { return values.ValueOf(ctx.Get(name)) } }
 | expr PROPERTY { $$ = makeObjectPropertyExpr($1, $2) }
 | expr '[' expr ']' { $$ = makeIndexExpr($1, $3) }
+| '(' expr DOTDOT expr ')' { $$ = makeRangeExpr($2, $4) }
 | '(' cond ')' { $$ = $2 }
 ;
 

diff --git a/expressions/expressions_test.go b/expressions/expressions_test.go
@@ -6,6 +6,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/osteele/liquid/values"
 	"github.com/stretchr/testify/require"
 )
 
@@ -27,6 +28,7 @@ var evaluatorTests = []struct {
 	// Attributes
 	{`hash.a`, "first"},
 	{`hash.b.c`, "d"},
+	{`hash["b"].c`, "d"},
 	{`hash.x`, nil},
 	{`fruits.first`, "apples"},
 	{`fruits.last`, "plums"},
@@ -44,7 +46,14 @@ var evaluatorTests = []struct {
 	{`hash[1]`, nil},
 	{`hash.c[0]`, "r"},
 
+	// Range
+	{`(1..5)`, values.NewRange(1, 5)},
+	{`(1..range.end)`, values.NewRange(1, 5)},
+	{`(1..range["end"])`, values.NewRange(1, 5)},
+	{`(range.begin..range.end)`, values.NewRange(1, 5)},
+
 	// Expressions
+	{`(1)`, 1},
 	{`(n)`, 123},
 
 	// Operators
@@ -116,6 +125,10 @@ var evaluatorTestBindings = (map[string]interface{}{
 		"c": []string{"r", "g", "b"},
 	},
 	"hash_with_size_key": map[string]interface{}{"size": "key_value"},
+	"range": map[string]interface{}{
+		"begin": 1,
+		"end":   5,
+	},
 })
 
 func TestEvaluateString(t *testing.T) {

diff --git a/expressions/statements.go b/expressions/statements.go
@@ -34,10 +34,10 @@ type Loop struct {
 }
 
 type loopModifiers struct {
-	Limit    *int
-	Offset   int
+	Limit    Expression
+	Offset   Expression
+	Cols     Expression
 	Reversed bool
-	Cols     int
 }
 
 // A When is a parse of a {% when %} clause

diff --git a/expressions/statements_test.go b/expressions/statements_test.go
@@ -10,6 +10,7 @@ func TestParseStatement(t *testing.T) {
 	stmt, err := ParseStatement(AssignStatementSelector, "a = b")
 	require.NoError(t, err)
 	require.Equal(t, "a", stmt.Assignment.Variable)
+	require.Implements(t, (*Expression)(nil), stmt.Assignment.ValueFn)
 
 	stmt, err = ParseStatement(CycleStatementSelector, "'a', 'b'")
 	require.NoError(t, err)
@@ -27,9 +28,12 @@ func TestParseStatement(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, "x", stmt.Loop.Variable)
 	require.True(t, stmt.Loop.Reversed)
-	require.Equal(t, 2, stmt.Loop.Offset)
+
+	require.Nil(t, stmt.Loop.Cols)
 	require.NotNil(t, stmt.Loop.Limit)
-	require.Equal(t, 3, *stmt.Loop.Limit)
+	require.Implements(t, (*Expression)(nil), stmt.Loop.Limit)
+	require.NotNil(t, stmt.Loop.Offset)
+	require.Implements(t, (*Expression)(nil), stmt.Loop.Offset)
 
 	stmt, err = ParseStatement(WhenStatementSelector, "a, b")
 	require.NoError(t, err)