tasks a-s

Task/Execute-a-Markov-algorithm/Go/execute-a-markov-algorithm-1.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+    "fmt"
+    "strings"
+)
+
+type testCase struct {
+    ruleSet, sample, output string
+}
+
+var testSet []testCase // initialized in separate source file
+
+func main() {
+    fmt.Println("validating", len(testSet), "test cases")
+    var failures bool
+    for i, tc := range testSet {
+        if r := ma(tc.ruleSet, tc.sample); r != tc.output {
+            fmt.Println("test", i+1, "fail")
+            failures = true
+        }
+    }
+    if !failures {
+        fmt.Println("no failures")
+    }
+}
+
+type rule struct {
+    pat  string
+    rep  string
+    term bool
+}
+
+func ma(rs, s string) string {
+    // compile rules per task description
+    var rules []rule
+    for _, line := range strings.Split(rs, "\n") {
+        if line == "" || line[0] == '#' {
+            continue
+        }
+        a := strings.Index(line, "->")
+        if a == -1 {
+            fmt.Println("invalid rule:", line)
+            return ""
+
+        }
+        pat := line[:a]
+        for {
+            if pat == "" {
+                b := strings.Index(line[a+2:], "->")
+                if b == -1 {
+                    fmt.Println("invalid rule:", line)
+                    return ""
+                }
+                a += 2 + b
+                pat = line[:a]
+                continue
+            }
+            last := pat[len(pat)-1]
+            if last != ' ' && last != '\t' {
+                break
+            }
+            pat = pat[:len(pat)-1]
+        }
+        rep := line[a+2:]
+        for rep > "" && (rep[0] == ' ' || rep[0] == '\t') {
+            rep = rep[1:]
+        }
+        var term bool
+        if rep > "" && rep[0] == '.' {
+            term = true
+            rep = rep[1:]
+        }
+        rules = append(rules, rule{pat, rep, term})
+    }
+    // execute algorithm per WP
+    for r := 0; r < len(rules); {
+        pat := rules[r].pat
+        if f := strings.Index(s, pat); f == -1 {
+            r++
+        } else {
+
+            s = s[:f] + rules[r].rep + s[f+len(pat):]
+            if rules[r].term {
+                break
+            }
+            r = 0
+        }
+    }
+    return s
+}

Task/Execute-a-Markov-algorithm/Go/execute-a-markov-algorithm-2.go

@@ -0,0 +1,20 @@
+package main
+
+func init() {
+    testSet = []testCase{
+        {
+`# This rules file is extracted from Wikipedia:
+# http://en.wikipedia.org/wiki/Markov_Algorithm
+A -> apple
+B -> bag
+S -> shop
+T -> the
+the shop -> my brother
+a never used -> .terminating rule`,
+            "I bought a B of As from T S.",
+            "I bought a bag of apples from my brother."},
+        {
+`# Slightly modified from the rules on Wikipedia
+A -> apple
+B -> bag
+...