ivy/talks: add support files for running the demos

Change-Id: Ife060cfa993743cd650b4c46092ac2b6f4f201b9

talks/demo.hoc

@@ -0,0 +1,5 @@
+23
+2*log(10)
+1e100
+2^64
+0x234

talks/demo.ivy

@@ -0,0 +1,82 @@
+#This is ivy. Each step in the demo is one line of input followed by some output.
+# Arithmetic
+23
+23 + 45
+# Rationals
+1/3
+1/3 + 4/5
+1.2
+# Big numbers
+1e10       # Still an integer.
+1e100      # Still an integer.
+2**64
+2**640
+2**6400
+# Vectors
+1 2 3
+1 2 3 + 4 5 6
+23 + 1 2 3
+1 << 1 2 3 4 5
+iota 10
+2 ** iota 100
+(2 ** iota 100) == (1<<iota 100)
+# Reduction
+iota 15
+1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 +14 + 15
++/iota 15
+1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10
+*/iota 10
+*/iota 100
+# Type this: */iota 10000
+max/2 34 42 233 2 2 521 14 1 4 1 55 133 
+# Shapes
+5 rho 1
+5 5 rho 1
+5 5 rho 25
+5 5 rho iota 25
+3 5 5 rho iota 125
+x = 5 5 rho iota 75
+x
+x/2
+x**2
+x**3
+x**10
+# Inner product
+x = 2**iota 5; x
+y = 3**iota 5; y
+x +.* y
+# Outer product
+x o.* y
+x o.== x
+# Random numbers
+?100
+?100
+?10 rho 100
+x = ?10 rho 100
+x
+# Indexing
+x[1]
+x[1 9 3]
+up x
+x[up x]
+x[down x]
+# Rolls of a die
+?6
+10 rho 6
+?10 rho 6
+x = ?10 rho 6; x
+(iota 6) o.== x
++/(iota 6) o.== x
++/(iota 6) o.== ?60000 rho 6
+# A big number calculator
+*/iota 100
+2**64
+2**iota 64
+-1+2**63
+)base 16
+_
+1<<iota 10
+(2**40)-1
+)obase 10
+_
+# And lots more...

talks/script.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+)
+
+func main() {
+	flag.Parse()
+	if flag.NArg() != 2 {
+		log.Fatal("Usage: script program filename")
+	}
+	text, err := ioutil.ReadFile(flag.Arg(1))
+	cmd := exec.Command(flag.Arg(0))
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	input, err := cmd.StdinPipe()
+	ck(err)
+	err = cmd.Start()
+	ck(err)
+	scan := bufio.NewScanner(os.Stdin)
+	for scan.Scan() {
+		// User typed something; step back across the newline.
+		if len(scan.Bytes()) > 0 {
+			// User typed a non-empty line of text; send that.
+			line := []byte(fmt.Sprintf("%s\n", scan.Bytes()))
+			_, err = input.Write(line)
+		} else {
+			// User typed newline; send next line of file's text.
+			if len(text) == 0 {
+				break
+			}
+			for i := 0; i < len(text); i++ {
+				if text[i] == '\n' {
+					os.Stdout.Write(text[:i+1])
+					_, err = input.Write(text[:i+1])
+					text = text[i+1:]
+					break
+				}
+			}
+		}
+		ck(err)
+	}
+	ck(scan.Err())
+}
+
+func ck(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+}