Initial Commit

internal/parser/lexer.go

@@ -0,0 +1,20 @@
+package parser
+
+import (
+	"github.com/alecthomas/participle/v2/lexer"
+)
+
+var lex = lexer.MustSimple([]lexer.SimpleRule{
+	{Name: "header", Pattern: `TAF (AMD|COR)? ?`},
+	{Name: "Remark", Pattern: `RMK .*`},
+	{Name: "Number", Pattern: `\d+`},
+	{Name: "Modifier", Pattern: `[+-]|VC`},
+	{Name: "Prob", Pattern: "PROB"},
+	{Name: "Slash", Pattern: `/`},
+	{Name: "Descriptor", Pattern: `MI|BC|DR|BL|SH|TS|FZ|PR`},
+	{Name: "Precip", Pattern: `DZ|RA|SN|SG|IC|PL|GR|GS|UP`},
+	{Name: "Obscur", Pattern: "BR|FG|FU|DU|SA|HZ|PY|VA"},
+	{Name: "Phenom", Pattern: "PO|SQ|FC|SS|DS"},
+	{Name: "Ident", Pattern: `[A-Z]+`},
+	{Name: "WS", Pattern: `[ \t\n\r]+`},
+})

internal/parser/parser.go

@@ -0,0 +1,98 @@
+package parser
+
+import (
+	"github.com/alecthomas/participle/v2"
+	"github.com/alecthomas/participle/v2/lexer"
+)
+
+type AST struct {
+	Items []*Item `@@*`
+}
+
+type Item struct {
+	Pos          lexer.Position
+	Time         *string       `( @Number "Z" WS`
+	Valid        *ValidPair    `  @@`
+	Probability  *Probability  `| @@`
+	Change       *Change       `| @@`
+	WindSpeed    *WindSpeed    `| @@`
+	Visibility   *Visibility   `| @@`
+	SkyCondition *SkyCondition `| @@`
+	Vicinity     *Vicinity     `| @@`
+	Weather      *Weather      `| @@`
+	Temperature  *Temperature  `| @@`
+	Flag         *Flag         `| @@`
+	Remark       *string       `| @Remark`
+	ID           *string       `| @Ident ) WS?`
+}
+
+type ValidPair struct {
+	Pos   lexer.Position
+	Start string `@Number "/"`
+	End   string `@Number`
+}
+
+type Probability struct {
+	Pos   lexer.Position
+	Value string `Prob @Number`
+	Time  string `(WS @Number)?`
+}
+
+type WindSpeed struct {
+	Pos       lexer.Position
+	WindShear string `("WS" @Number "/")?`
+	Variable  bool   `@"VRB"?`
+	Value     string `@Number`
+	Gusts     string `("G" @Number)?`
+	Unit      string `@("MPS"|"KMH"|"KT")`
+}
+
+type Visibility struct {
+	Pos   lexer.Position
+	Plus  bool   `@"P"?`
+	Value string `@Number @WS? @(Number? "/" Number)?`
+	Unit  string `@"SM"?`
+}
+
+type SkyCondition struct {
+	Pos       lexer.Position
+	Type      string `@("FEW"|"SCT"|"BKN"|"OVC"|"VV"|"SKC")`
+	Altitude  string `@Number?`
+	CloudType string `@("CB"|"TCU")?`
+}
+
+type Vicinity struct {
+	Pos           lexer.Position
+	Descriptor    string `"VC" ( @Descriptor`
+	Precipitation string `     | @Precip )`
+}
+
+type Weather struct {
+	Pos           lexer.Position
+	Modifier      string `@Modifier?`
+	Descriptor    string `@Descriptor?`
+	Precipitation string ` ( @Precip`
+	Obscuration   string ` | @Obscur`
+	Other         string ` | @Phenom )`
+}
+
+type Change struct {
+	Pos   lexer.Position
+	Type  string     `@("FM"|"BECMG"|"TEMPO")`
+	Time  string     `@Number?`
+	Valid *ValidPair `WS? @@?`
+}
+
+type Temperature struct {
+	Pos   lexer.Position
+	Type  string `@("TX"|"TN")`
+	Value string `@Number "/"`
+	Time  string `@Number "Z"`
+}
+
+type Flag struct {
+	Pos   lexer.Position
+	CAVOK bool `@"CAVOK"`
+}
+
+var Parser = participle.MustBuild[AST](participle.Lexer(lex))