retrofitted arithmetic functions

ast/eval.go

@@ -89,6 +89,11 @@ func (in *Token) Eval(funcs FuncTable, vars VarTable) *Token {
                 inner = &Token{inner: inner}
             }
             res = funct.CallFunction(inner.Next, vars, funcs).Eval(funcs, vars)
+            if res == nil {
+                // function failed. logging is its responsibility
+                return nil
+            }
+
             res.Append(in.Next)
 
         } else {

stdlib/arith.go

@@ -0,0 +1,214 @@
+/*   SHS: Syntactically Homogeneous Shell
+ *   Copyright (C) 2019  Aidan Hahn
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package stdlib
+
+import (
+    "fmt"
+    "strconv"
+    "gitlab.com/whom/shs/ast"
+    "gitlab.com/whom/shs/log"
+)
+
+// PKG WIDE TODO: BIGNUM SYSTEM
+// then write actually optimal routines once it is in place
+// perhaps we simply write out arithmetic routines that operate on the strings
+// then we need not worry about storage length.
+
+func add(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+
+    in = in.Eval(f, a)
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to ADD", "add")
+            return nil
+        }
+
+        token := i.Value()
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "add")
+                    return nil
+                }
+
+                res += n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "add")
+                return nil
+            }
+
+            res += float64(n)
+        }
+    }
+
+    t := &ast.Token{Tag: ast.NUMBER}
+    t.Set(fmt.Sprintf("%f", res))
+    return t
+}
+
+func sub(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+    var sub float64
+
+    in = in.Eval(f, a)
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to SUB", "sub")
+            return nil
+        }
+
+        token := i.Value()
+        isFloat := false
+        var inner float64
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "sub")
+                    return nil
+                }
+
+                inner = n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "sub")
+                return nil
+            }
+
+            inner = float64(n)
+        }
+
+        if i.Next != nil {
+            sub += inner
+        } else {
+            res = inner
+        }
+    }
+
+    t := &ast.Token{Tag: ast.NUMBER}
+    t.Set(fmt.Sprintf("%f", res - sub))
+    return t
+}
+
+func mult(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    res := 1.0
+
+    in = in.Eval(f, a)
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to MULT", "mult")
+            return nil
+        }
+
+        token := i.Value()
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "mult")
+                    return nil
+                }
+
+                res *= n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "mult")
+                return nil
+            }
+
+            res *= float64(n)
+        }
+    }
+
+    t := &ast.Token{Tag: ast.NUMBER}
+    t.Set(fmt.Sprintf("%f", res))
+    return t
+}
+
+func div(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+
+    in = in.Eval(f, a)
+
+    for i := in; i != nil; i = i.Next {
+        inner := 0.0
+
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to DIV", "div")
+            return nil
+        }
+
+        token := i.Value()
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "div")
+                    return nil
+                }
+
+                inner = n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "div")
+                return nil
+            }
+
+            inner = float64(n)
+        }
+
+        if i == in {
+            res = inner
+        } else {
+            res = res / inner
+        }
+    }
+
+    t := &ast.Token{Tag: ast.NUMBER}
+    t.Set(fmt.Sprintf("%f", res))
+    return t
+}

stdlib/bool.go

@@ -24,6 +24,8 @@ import (
 )
 
 func not(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    in = in.Eval(ft, vt)
+
     if in.Tag != ast.BOOL {
         log.Log(log.ERR, "non-bool argument to 'not'", "not")
         return nil
@@ -96,10 +98,24 @@ func eq(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
                 out = "F"
             }
 
-        case ast.NUMBER, ast.STRING, ast.BOOL:
+        case ast.STRING, ast.BOOL:
             if in.Value() != second.Value() {
                 out = "F"
             }
+
+        case ast.NUMBER:
+            l_val, parse_err := strconv.ParseFloat(in.Value(), 64)
+            r_val, parse_err := strconv.ParseFloat(second.Value(), 64)
+            if parse_err != nil {
+                log.Log(log.ERR,
+                    "error parsing number: "+parse_err.Error(),
+                    "eq")
+                return nil
+            }
+
+            if l_val != r_val {
+                out = "F"
+            }
         }
     }
 

stdlib/stdlib.go

@@ -95,6 +95,34 @@ func GenFuncTable() ast.FuncTable {
             Args:              1,
         },
 
+        "+": &ast.Function{
+            Function:      add,
+            Name:        "add",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
+        "-": &ast.Function{
+            Function:      sub,
+            Name:        "sub",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
+        "*": &ast.Function{
+            Function:     mult,
+            Name:       "mult",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
+        "/": &ast.Function{
+            Function:      div,
+            Name:        "div",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
     }
 
     return stdlib