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|
package driver
import (
"fmt"
"os"
"strings"
"testing"
"github.com/nihei9/vartan/grammar"
"github.com/nihei9/vartan/spec"
)
func TestParserWithConflicts(t *testing.T) {
tests := []struct {
caption string
specSrc string
src string
cst *Node
}{
{
caption: "when a shift/reduce conflict occurred, we prioritize the shift action",
specSrc: `
expr
: expr assign expr
| id
;
id: "[A-Za-z0-9_]+";
assign: '=';
`,
src: `foo=bar=baz`,
cst: nonTermNode("expr",
nonTermNode("expr",
termNode("id", "foo"),
),
termNode("assign", "="),
nonTermNode("expr",
nonTermNode("expr",
termNode("id", "bar"),
),
termNode("assign", "="),
nonTermNode("expr",
termNode("id", "baz"),
),
),
),
},
{
caption: "when a reduce/reduce conflict occurred, we prioritize the production defined earlier in the grammar",
specSrc: `
s
: a
| b
;
a
: id
;
b
: id
;
id: "[A-Za-z0-9_]+";
`,
src: `foo`,
cst: nonTermNode("s",
nonTermNode("a",
termNode("id", "foo"),
),
),
},
}
for _, tt := range tests {
t.Run(tt.caption, func(t *testing.T) {
ast, err := spec.Parse(strings.NewReader(tt.specSrc))
if err != nil {
t.Fatal(err)
}
b := grammar.GrammarBuilder{
AST: ast,
}
g, err := b.Build()
if err != nil {
t.Fatal(err)
}
gram, err := grammar.Compile(g, grammar.SpecifyClass(grammar.ClassSLR))
if err != nil {
t.Fatal(err)
}
p, err := NewParser(gram, strings.NewReader(tt.src), MakeCST())
if err != nil {
t.Fatal(err)
}
err = p.Parse()
if err != nil {
t.Fatal(err)
}
fmt.Printf("CST:\n")
PrintTree(os.Stdout, p.CST())
testTree(t, p.CST(), tt.cst)
})
}
}
|
