Implement if statements and regex lexer

ast.go

@@ -32,6 +32,17 @@ type AST struct {
 func (ast *AST) Execute() error {
 	// For each command in AST
 	for _, cmd := range ast.Commands {
+		// Execute current command
+		err := executeCmd(cmd)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Parse and execute command
+func executeCmd(cmd *Command) error {
 	// If parsing variables
 	if cmd.Vars != nil {
 		// For each variable
@@ -55,7 +66,6 @@ func (ast *AST) Execute() error {
 				Vars[Var.Key] = val
 			}
 		}
-			// If parsing function calls
 	} else if cmd.Calls != nil {
 		// For each function call
 		for _, Call := range cmd.Calls {
@@ -66,18 +76,27 @@ func (ast *AST) Execute() error {
 			}
 		}
 	} else if cmd.Ifs != nil {
+		// For each if statement
 		for _, If := range cmd.Ifs {
+			// Get condition value
 			condVal, err := callIfFunc(ParseValue(If.Condition))
 			if err != nil {
-					return err
+				return fmt.Errorf("%s: %s", If.Condition.Pos, err)
 			}
+			// Attempt to assert condition type as bool
 			condBool, ok := condVal.(bool)
 			if !ok {
 				return errors.New("condition must be a boolean")
 			}
+			// If condition is true
 			if condBool {
-					_, err := CallFunction(If.Action)
-					return err
+				// For each inner command
+				for _, InnerCmd := range If.InnerCmds {
+					// Execute command recursively
+					err := executeCmd(InnerCmd)
+					if err != nil {
+						return fmt.Errorf("%s: %s", InnerCmd.Pos, err)
+					}
 				}
 			}
 		}
@@ -88,15 +107,17 @@ func (ast *AST) Execute() error {
 // Command stores any commands encountered while parsing a script
 type Command struct {
 	Pos   lexer.Position
+	Tokens []lexer.Token
 	Vars  []*Var      `( @@`
 	Ifs   []*If       `| @@`
 	Calls []*FuncCall `| @@)`
 }
 
+// If stores any if statements encountered while parsing a script
 type If struct {
 	Pos       lexer.Position
-	Condition *Value    `"if" @@`
-	Action    *FuncCall `"then" @@`
+	Condition *Value     `"if" @@ "{"`
+	InnerCmds []*Command `@@*"}"`
 }
 
 // FuncCall stores any function calls encountered while parsing a script
@@ -124,8 +145,7 @@ type Var struct {
 type Value struct {
 	Pos     lexer.Position
 	String  *string     `  @String`
-	Float   *float64    `| @Float`
-	Integer *int64      `| @Int`
+	Number   *float64    `| @Number`
 	Bool    *Bool       `| @("true" | "false")`
 	SubCmd  *FuncCall   `| "(" @@ ")"`
 	VarVal  *string     `| "$" @Ident`
@@ -152,7 +172,8 @@ type Expression struct {
 	RightSegs []*ExprRightSeg `@@*`
 }
 
+// ExprRightSeg stores segments of the right side of an expression
 type ExprRightSeg struct {
-	Op    string `@( ">" | ">" "=" | "<" | "<" "=" | "!" "=" | "=" "=" | "+" | "-" | "*" | "/" | "^" | "%")`
+	Op    string `@Operator`
 	Right *Value `@@`
 }

lexer.go

@@ -0,0 +1,17 @@
+package scpt
+
+import (
+	"github.com/alecthomas/participle/lexer"
+	"github.com/alecthomas/participle/lexer/stateful"
+)
+
+// Create custom stateful regex lexer
+var scptLexer = lexer.Must(stateful.NewSimple([]stateful.Rule{
+	{"Ident", `[a-zA-Z]\w*`, nil},
+	{"String", `"[^"]*"`, nil},
+	{"Number", `(?:\d*\.)?\d+`, nil},
+	{"Punct", `[-[!@#$&()_{}\|:;"',.?/]|]`, nil},
+	{"Whitespace", `[ \t\r\n]+`, nil},
+	{"Comment", `#[^\n]+`, nil},
+	{"Operator", `(>=|<=|>|<|==|!=)|[-+*/^%]`, nil},
+}))

scpt.go

@@ -58,8 +58,12 @@ func AddVars(varMap map[string]interface{}) {
 
 // Parse uses participle to parse a script from r into a new AST
 func Parse(r io.Reader) (*AST, error) {
-	// Build parser from empty AST struct
-	parser, err := participle.Build(&AST{})
+	// Build parser from empty AST struct with custom lexer
+	parser, err := participle.Build(
+		&AST{},
+		participle.Lexer(scptLexer),
+		participle.Elide("Whitespace", "Comment"),
+		)
 	if err != nil {
 		return nil, err
 	}
@@ -83,12 +87,9 @@ func ParseValue(val *Value) (interface{}, error) {
 	} else if val.Bool != nil {
 		// Return dereferenced Bool converted to bool
 		return bool(*val.Bool), nil
-	} else if val.Float != nil {
+	} else if val.Number != nil {
 		// Return dereferenced float
-		return *val.Float, nil
-	} else if val.Integer != nil {
-		// Return dereferenced integer
-		return *val.Integer, nil
+		return *val.Number, nil
 	} else if val.SubCmd != nil {
 		// Return reference to subcommand
 		return val.SubCmd, nil

test.scpt

@@ -3,5 +3,14 @@ display-dialog "Goodbye" with title 21 with type "error"
 do-shell-script "notify-send Test Notification"
 do-shell-script {"echo " + (display-dialog {"Test " + "2"} with title 30 with type "entry" with default "text")}
 set x to $y
-if {3 == 4} then display-dialog "What? Why is 3 equal to 4?" with title "What?!" with type "info"
-if {3 == 3} then display-dialog "3 is equal to 3!" with title "New Discovery" with type "info"
+
+if {3 == 3} {
+    set x to "hi"
+    do-shell-script {"echo " + $x}
+    display-dialog "3 is equal to 3!" with title "New Discovery" with type "info"
+    if {3 == 4} {
+        display-dialog "What? Why is 3 equal to 4?" with title "What?!" with type "error"
+        do-shell-script "echo hi"
+    }
+}
+