func scan(c *scanner.Scanner) token {
c.EatWhitespaceAndComments()
if c.Peek() == '/' {
c.ReadChar()
return token{"Divide", ""}
} else if c.EndOfFile() {
log.Println("Found EOF")
return token{"EOF", ""}
} else if c.Peek() == '-' {
c.ReadChar()
chr := c.ReadChar()
if chr != '>' {
c.Fail("Found -, and expected a \"to\" statement(->) but found ", chr)
}
return token{"To", ""}
} else if utils.IsAlphabetic(c.Peek()) {
word := c.ReadWord()
if word == "States" {
return token{"States", ""}
} else if word == "Edges" {
return token{"Edges", ""}
}
return token{"Word", word}
} else if utils.IsNumeric(c.Peek()) {
integer := strconv.Itoa(c.ReadNumber())
return token{"Integer", integer}
} else {
c.Fail("Unexpected keyword ", c.Peek())
}
return token{}
}
func (c *Scanner) ReadWord() string {
if !utils.IsAlphabetic(c.Peek()) {
c.Fail("Could not read word")
}
word := string(c.ReadChar())
for !c.EndOfFile() {
if utils.IsAlphabetic(c.Peek()) || utils.IsNumeric(c.Peek()) {
word += string(c.ReadChar())
} else if utils.IsWhitespace(c.Peek()) || c.Peek() == '/' {
break
} else {
c.Fail("Reading a word failed, found '", word, "' but then unexpected ", string(c.Peek()))
}
}
return word
}
func (c *Scanner) ReadNumber() int {
number := ""
for !c.EndOfFile() {
if utils.IsNumeric(c.Peek()) {
number += string(c.ReadChar())
} else if utils.IsWhitespace(c.Peek()) || c.Peek() == '/' {
break
} else {
c.Fail("Expected whitespace after the number "+number+", but got ", string(c.Peek()))
}
}
if len(number) == 0 {
c.Fail("Did not read any number")
}
numbasint, err := strconv.Atoi(number)
if err != nil {
c.Fail("Could not convert to number. Something really bad happened, and should never happen. Please contact the developers at https://github.com/jbossen/P7-code")
}
return numbasint
}