Some early lexer ideas

go.mod

@@ -0,0 +1,3 @@
+module github.com/tgckpg/mmqlengine
+
+go 1.19

main.go

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+package main
+
+import (
+)
+
+func main() {
+    
+}

mmql/definitions.go

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+package mmql
+
+type TokenType int
+
+type Token struct {
+    Type TokenType
+    Value string
+}
+
+const (
+    K_SPACES = "\t\n\r "
+    K_BRACKETS = "()[]{}"
+    K_QUOTES = "'\"`"
+)
+
+const (
+    UnknownToken TokenType = iota
+    KeywordToken
+    BracketToken
+    SquareBracketToken
+    CurlyBracketToken
+    SingleQuote
+    DoubleQuote
+    AccuteAccentQuote
+)
+
+var KEYWORDS = []string {
+    "ANYWHERE",
+    "BOUGHT",
+    "BUY",
+    "CREATE",
+    "EVERY",
+    "EXCHANGE",
+    "FOR",
+    "FROM",
+    "GET",
+    "LIMIT",
+    "LIST",
+    "OF",
+    "SELL",
+    "SOLD",
+    "TRIGGER",
+    "TRIGGERS",
+    "TYPE",
+    "UPDATE",
+    "WITH",
+}
+
+var STATEMENTS = map[string] func() ( IStatement, error ) {
+    "BUY": _buyStatement,
+}

mmql/lexer.go

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+package mmql
+
+import "fmt"
+
+type Lexer struct {
+    expect TokenType
+}
+
+func ( this *Lexer ) Parse( line string ) {
+
+    for i, r := range line {
+        fmt.Printf( "%d: %s\n", i, string( r ) )
+    }
+}

mmql/lexer_test.go

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+package mmql
+
+import "testing"
+
+func TestParse( t *testing.T ) {
+    lexer := Lexer{}
+    lexer.Parse( `
+BUY 1 SHARES OF BTC_ETF
+  FOR 10 USD
+  FROM "MyBrokerAccount"
+  WITH LIMIT OF PURCHASING_POWER( "MyBrokerAccount", "QQQ" )
+  FOR EVERY
+    1 BTC OF USD_BTC SOLD
+        FROM "CoinBase"
+` )
+
+}

mmql/statements.go

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+package mmql
+
+type IStatement interface {
+}
+
+type ActionStatement struct {
+    IStatement
+}

mmql/stmt_buy.go

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+package mmql
+
+/*
+EXPECT: BUY
+THEN EXPECT: [AmountType] OF [ProductType]
+THEN EXPECT: FOR [AmountType]
+THEN EXPECT: FROM [ExchangeType]
+THEN OPT EXPECT: [ExchangeType]
+THEN OPT EXPECT: [AND|OR]
+    THEN EXPECT: [ActionExpression]
+THEN OPT EXPECT: FOR EVERY
+    THEN EXPECT: [AmountType] OF [ProductType]
+    THEN EXPECT: [SOLD|BOUGHT] FROM [ExchangeType]
+*/
+
+func _buyStatement() ( IStatement, error ) {
+    a := ActionStatement{}
+    var b IStatement = a
+    return b, nil
+}
+/*
+func _buyStatement( lexer *Lexer ) ( ActionStatement, error ) {
+
+    token := lexer.GetToken()
+    if token.Type == KeywordToken && token.Value == "BUY" {
+    } else {
+
+    }
+}
+*/