add variables!

README.md

@@ -102,20 +102,27 @@ Conceptually clearer to have all the multiplications first and then all the divi
 - [x] Add show more info version
 - [x] Scalar multiplication and division
 - [ ] Program into a small device, like a calculator?
-- [ ] Think of some way of calling bc
-- [ ] Think how to integrate with squiggle.c to draw samples
+- [-] Think of some way of calling bc
+- [x] Think how to integrate with squiggle.c to draw samples
+  - [x] Copy the time to botec go code
+  - [ ] Define samplers
+  - [ ] Call those samplers when operating on distributions that can't be operted on algebraically
 - [ ] Think about how to draw a histogram from samples
 - [x] Display output more nicely, with K/M/B/T
 - [ ] Consider the following: make this into a stack-based DSL, with:
   - Variables that can be saved to and then displayed
   - Other types of distributions, particularly beta distributions? => But then this requires moving to bags of samples. It could still be ~instantaneous though.
+- Figure out syntax for
+  - Maps
+  - Joint types
+  - Enums
 
 Some possible syntax for a more expressive stack-based DSL
 
 ```
 1B to 20B
 * 1 to 100
-/ beta(1, 2)
+/ beta 1 2 # or b 1 2
 =: x # content of the stack at this point saved into x
 
 1 to 10

f2.go

@@ -31,7 +31,7 @@ func parseLineErr(err_msg string) (string, Dist, error) {
 	fmt.Println(err_msg)
 	return "", Dist{}, errors.New(err_msg)
 }
-func parseLine(line string) (string, Dist, error) {
+func parseLine(line string, vars map[string]Dist) (string, Dist, error) {
 
 	words := strings.Split(strings.TrimSpace(line), " ")
 	op := ""
@@ -56,11 +56,16 @@ func parseLine(line string) (string, Dist, error) {
 	case 0:
 		return parseLineErr("Operator must have operand; can't operate on nothing")
 	case 1:
+		var_word, var_word_exists := vars[words[0]]
 		single_float, err1 := strconv.ParseFloat(words[0], 64)
-		if err1 != nil {
-			return parseLineErr("Trying to operate on a scalar, but scalar is not a float")
+		switch {
+		case var_word_exists:
+			dist = var_word
+		case err1 == nil:
+			dist = Dist{Type: "Lognormal", Lognormal: Lognormal{low: single_float, high: single_float}, Samples: nil}
+		case err1 != nil && !var_word_exists:
+			return parseLineErr("Trying to operate on a scalar, but scalar is neither a float nor a variable")
 		}
-		dist = Dist{Type: "Lognormal", Lognormal: Lognormal{low: single_float, high: single_float}, Samples: nil}
 	case 2:
 		new_low, err1 := strconv.ParseFloat(words[0], 64)
 		new_high, err2 := strconv.ParseFloat(words[1], 64)
@@ -105,7 +110,7 @@ func joinDists(old_dist Dist, new_dist Dist, op string) (Dist, error) {
 	default:
 		fmt.Printf("For now, can't do anything besides multiplying lognormals\n")
 	}
-	return old_dist, errors.New("Error blah blah")
+	return old_dist, errors.New("Can't combine distributions in this way")
 }
 
 /* Pretty print distributions */
@@ -157,6 +162,9 @@ func prettyPrintDist(dist Dist) {
 func main() {
 	reader := bufio.NewReader(os.Stdin)
 	old_dist := Dist{Type: "Lognormal", Lognormal: Lognormal{low: 1, high: 1}, Samples: nil} // Could also just be a scalar
+	vars := make(map[string]Dist)
+	// Could eventually be a more complex struct with:
+	// { Dist, VariableMaps, ConfigParams } or smth
 	// fmt.Printf("Hello world")
 
 EventForLoop:
@@ -175,17 +183,22 @@ EventForLoop:
 				fmt.Println(general_err_msg)
 				continue EventForLoop
 			case words[0] == "debug" || words[0] == "d":
-				fmt.Printf("%v\n", old_dist)
+				fmt.Printf("Old dist: %v\n", old_dist)
+				fmt.Printf("Vars: %v\n", vars)
+				continue EventForLoop
+			case words[0] == "=:" && len(words) == 2:
+				// fmt.Println("Variables not yet implemented")
+				vars[words[1]] = old_dist // is this a copy?
 				continue EventForLoop
 				// Other possible cases:
 				// Save to file
 				// Sample n samples
 				// Save stack to a variable?
-				// Define a function? No, too much of a nerdsnipe
+				// Define a function? No, too much of a nerdsnipea
 			}
 		}
 
-		op, new_dist, err := parseLine(input)
+		op, new_dist, err := parseLine(input, vars)
 		if err != nil {
 			continue EventForLoop
 		}